Display Device with Light Shield

ABSTRACT

A display of an electric device includes a plurality of separated transparent electrode blocks, which are configured to provide one or more of supplemental features such as touch recognition. Signal paths between the transparent electrode blocks and the driver for the supplemental feature are implemented with a plurality of conductive lines placed under positioned under one or more planarization layers. The conductive lines implementing the signal paths are routed across the display area, directly toward a non-display area where drive-integrated circuits are located.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure generally relates to electronic devices, and moreparticularly to electronic devices with displays and methods ofmanufacturing the same.

Description of the Related Art

Electronic devices often include displays. For example, mobiletelephones and portable computers include displays for presentinginformation to a user. In addition to displaying information, displaysmay sport various supplemental features. For instance, a touch screenallows a user to interact with a device simply by touching the graphicalinterface displayed on the screen with fingers, stylus (pen) or otherobjects. With ease of use and versatility in operation, the touch screenhas been one of the most popular user interaction mechanism used in avariety of flat panel displays such as liquid crystal displays (LCDs)and organic light emitting diode (OLED) displays.

Conventionally, a discrete substrate provided with a matrix oftouch-driving lines and touch-sensing lines, which may be referred to asa touch panel, is overlaid on a display panel to provide thetouch-sensing functionality. However, placing a separate touch panel onthe display panel adds to the thickness and the weight of the displaypanel. Similar problems can result from adding separate components orsubstrates for such supplemental features, for instance tactile feedbackor pressure sensing function, to the displays. As such, attempts havebeen made to integrate components relating to those supplementalfeatures within the stacks of layers forming the display panel.

However, integrating the components relating to the supplementalfeatures (e.g., touch sensor, touch pressure sensor, tactile feedbacksensor) within a display panel can complicate the operation of thedisplay panel, and may even require some compromises in the displayqualities. For instance, conductive lines transmitting signals to andfrom the display areas in the display panel for an implementation oftouch-sensing, touch-pressure sensing or tactile feedback mechanism maygenerate unwanted parasitic capacitance with other components of thedisplay panel, which may result in visual defects (e.g., irregulartilting angle of liquid crystal molecules, line dim, moiré effects,etc.).

SUMMARY

The present disclosure generally relates to display panels provided withsupplemental functionalities such as touch sensing functionality, touchpressure sensing functionality and tactile feedback functionality, andmore particularly, to configuration of segmented electrode blocksarranged over a display area of a display panel for such supplementalfunctionalities.

In a display panel, some elements used in relation with a displayfunctionality can be configured to recognize touch inputs on the screen.For instance, some drivers such as a gate driver, a data driver and atouch driver, may be configured to provide signals for operating thedisplay pixels and for recognizing touch inputs made on the screen.Also, some electrodes and/or conductive layers in display pixels usedfor displaying image on the display panel can be configured to serve asa part of a touch sensor.

For instance, a display panel may be provided with a plurality oftransparent electrode blocks (i.e., pieces) provided over a display areaof the display panel, and each of the transparent electrode block isconfigured communicate with a touch driver via a signal path, which isformed of at least one common signal lines. The common signal lines aredisposed on a substrate, and the common signal liens are covered by alower planarization layer. The lower planarization layer is providedover the plurality of common signal lines in a thickness sufficient toprovide a planar surface over the common signal lines. A plurality ofgate lines, a plurality of data lines and a plurality ofthin-film-transistors (TFT) are provided on the planar surface providedby the lower planarization layer, and they form an array of pixelcircuits in the display area. That is, the gate lines and the data linesdefine a matrix of pixel regions, in which each pixel region is providedwith a pixel circuitry with one or more TFTs.

In this way, a display panel can be provided in a lighter weight, withthinner profile and can be manufactured with fewer parts in fewermanufacturing steps.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a laptop computer with a display, inaccordance with an embodiment of the present disclosure.

FIG. 1B is a front view of and a handheld electronic device with adisplay, in accordance with an embodiment of the present disclosure.

FIG. 2 is a schematic diagram of an exemplary electronic device with adisplay in accordance with an embodiment of the present disclosure.

FIG. 3A is a schematic illustration of an exemplary display panel with aplurality of transparent electrode blocks, in which each of thetransparent electrode blocks is connected to a common signal line andconfigured to operate in a self-capacitance touch sensor, according toan embodiment of the disclosure.

FIG. 3B is a schematic illustration of an exemplary display panel with aplurality of transparent electrode blocks, in which each of thetransparent electrode blocks is connected to a common signal line andconfigured to operate in a mutual-capacitance touch sensor, according toan embodiment of the disclosure.

FIG. 4 is a timing diagram showing exemplary timing of signals appliedto the transparent electrode blocks and the pixel electrodes of thepixels during display periods and during a touch sense period accordingto an embodiment of the disclosure.

FIG. 5A is a timing diagram showing an exemplary timing of a signal,which is used for providing multiple touch scanning periods within asingle frame, according to an embodiment of the disclosure.

FIG. 5B is a diagram illustrating how the total duration of a singleframe can be divided and allocated to accommodate a plurality of displayperiods and a plurality of touch scanning periods, according to anembodiment of the disclosure.

FIG. 6A is a schematic illustration showing an exemplary configurationof the common signal lines and the bypass lines in the display panels,according to an embodiment of the present disclosure.

FIG. 6B is a cross-sectional view showing an exemplary configuration forconnecting a common signal line to a transparent electrode block via abypass line, according to an embodiment of the present disclosure.

FIG. 6C is a schematic illustration showing the order in which the metallayers forming the common signal lines, the bypass lines, the gatelines, the data lines and the source/drain of the thin-film transistor,according to an embodiment of the present disclosure.

FIGS. 7A-7B illustrate cross-sectional views of a display panel duringmanufacturing steps, according to an embodiment of the presentdisclosure.

FIG. 8A illustrates a cross-sectional view of an exemplary embodiment inwhich at least some of the common signal lines are in direct contactwith the common electrode blocks via a contact hole made through theupper and lower planarization layers at a SL-VCOM contact region.

FIG. 8B illustrates cross-sectional views of the SL-VCOM contact regionshown in FIG. 8A during manufacturing steps, according to an embodimentof the present disclosure.

FIG. 9A is a top view and a cross-sectional side view illustrating anexemplary configuration of a common signal line provided under acoplanar structure thin-film transistor, according to an embodiment ofthe present disclosure.

FIG. 9B is a cross-sectional side view of an illustrative configurationof a common signal line, a bypass line and transparent electrode blocks,according to an embodiment of the present disclosure.

FIG. 10A is a top view of an exemplary configuration of metal linetraces in the non-display area of a display panel, according to anembodiment of the present disclosure.

FIG. 10B is a top view and a cross-sectional side view showing anexemplary configuration of metal line traces in the non-display area ofa display panel, according to an embodiment of the present disclosure.

FIG. 11A is a circuit diagram of illustrative stage in a gate drivercircuitry for a display, according to an embodiment of the presentdisclosure.

FIG. 11B is a top view of a capacitor provided in the stage of FIG. 11A,according to an embodiment of the present disclosure.

FIGS. 11C and 11D are cross-sectional side views of a capacitor providedin the stage of FIG. 11A, according to an embodiment of the presentdisclosure.

FIG. 12A is a circuit diagram of exemplary compensation circuitry, whichmay be provided in embodiments configured with the intra-frame pausedriving scheme, according to an embodiment of the present disclosure.

FIG. 12B is a timing diagram of illustrative operation of a gate driverprovided with the compensation circuitry of FIG. 12A, according to anembodiment of the present disclosure.

FIG. 13 is a schematic diagram showing an illustrative configuration ofthe common signal lines and their connections to the transparentelectrode blocks, according to an embodiment of the present disclosure.

FIGS. 14A-14F each illustrates an exemplary configuration of commonsignal lines for implementing signal paths between a driver to thecommon electrode blocks, according to the embodiments of the presentdisclosure.

FIG. 15A illustrates an exemplary configuration of common signal linesat the detour section.

FIG. 15B illustrates another exemplary configuration of common signallines at the detour section.

FIG. 16 is a schematic illustration showing an exemplary configurationof masking layer, according to an embodiment of the present disclosure.

FIGS. 17A-17E illustrate various exemplary configurations of a maskinglayer, according to embodiments of the present disclosure.

FIGS. 18A-18C illustrate exemplary configurations of common signal lineshaving a light shield, according to an embodiment of the presentdisclosure.

FIG. 19A illustrates exemplary configuration for connection a bypassline and a transparent electrode block at the BL-VCOM contact region,according to embodiments of the present disclosure.

FIG. 19B illustrates schematic cross-sectional views of the BL-VCOMcontact region during manufacturing, according to an embodiment of thepresent disclosure.

FIG. 20A illustrates an exemplary configuration of a set of bypass linesfor connecting a plurality of common signal lines (or dummy lines) to acommon electrode block.

FIG. 20B illustrates an exemplary configuration of a set of bypass linesfor connecting a plurality of common signal lines (or dummy lines) to acommon electrode block.

FIG. 20C illustrates an exemplary configuration of a set of bypass linesfor a common electrode block, in which one of the bypass lines extendstoward a first side of the common signal line (or dummy line) andanother one of the bypass lines extends toward a second side of thecommon signal line (or dummy line).

FIG. 20D illustrates an exemplary configuration of a set of bypass linesfor a common electrode block, in which a common signal line is providedwith a plurality of contact portions, each routed to a different pixelregions.

FIGS. 21A-21B illustrate an exemplary configuration of a display panelat the region between two adjacent transparent electrode blocks.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Example embodiments may be described herein with reference to aCartesian coordinate system in which the x-direction and the y-directioncan be equated to the horizontal (row) direction and the vertical(column) direction, respectively. However, one skilled in the art willunderstand that reference to a particular coordinate system is simplyfor the purpose of clarity, and does not limit the direction of thestructures to a particular direction or a particular coordinate system.

[Exemplary Electric Devices with Display]

Electronic devices may include displays used to display images to auser. Illustrative electronic devices that may be provided with displaysare shown in FIGS. 1A and 1B.

FIG. 1A shows how electronic device 10 may have the shape of a laptopcomputer having upper housing UH and lower housing LH. Components suchas keyboard INP1 and touchpad INP2 may be provided in the electronicdevice 10. Device 10 may have hinge structures HNG that allow upperhousing UH to rotate in directions about rotational axis AX relative tolower housing LH. Display panel PNL may be mounted in upper housing UH,in lower housing LH or in both upper housing UH and lower housing LH.Upper housing UH, which may sometimes referred to as a display housingor lid, may be placed in a closed position by rotating upper housing UHtowards lower housing LH about rotational axis AX. When display panelPNL is mounted across from upper housing UH to lower housing LH, displaypanel PNL may be a foldable display. Also, upper housing UH and lowerhousing LH may each include a separate display panel PNL.

FIG. 1B shows electronic device 10 provided in a form of a handhelddevice such as a mobile telephone, music player, gaming device, controlconsole unit in an automobile, or other compact device. In this type ofconfiguration for device 10, housing 12 may have opposing front and rearsurfaces. Display panel PNL may be mounted on a front face of housingHS. Display panel PNL may, if desired, have a display cover layer orother exterior layer that includes openings for components such asbutton BT, speakers SPK and camera CMR.

The configurations for device 10 that are shown in FIGS. 1A and 1B aremerely illustrative. In general, electronic device 10 may be a laptopcomputer, a computer monitor containing an embedded computer, a tabletcomputer, a mobile telephone, a media player, or other handheld orportable electronic device, a smaller device such as a wrist-watchdevice, a pendant device, or other wearable or miniature device, atelevision, a computer display that does not contain an embeddedcomputer, a gaming device, a navigation device, an embedded system suchas a system in which electronic equipment with a display is mounted in akiosk or in an automobile (e.g., dashboard, center console and controlpanel), or other electronic equipment.

Display panel PNL may be a touch sensitive display that includes a layerwith an array of transparent electrode blocks, which serves as a touchsensor. Display panel PNL may be a touch sensitive display that includesa layer with an array of transparent electrode blocks, which serves atouch sensor capable of measuring pressure of touch inputs. Displaypanel PNL may be a touch sensitive display that includes a layer with anarray of transparent electrode blocks, which provides tactile feedbackin response to touch inputs.

Displays for device 10 may, in general, include image pixels formed fromlight-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells,electrowetting pixels, electrophoretic pixels, liquid crystal display(LCD) components, or other suitable image pixel structures.

Embodiments in the present disclosure are described in the context ofLCDs, in particular, the In-Plane-Switching (IPS) mode LCD and theFringe-Field-Switching (FFS) mode LCD having both the common electrodesand the pixel electrodes arranged on one of the substrates that enclosethe liquid crystal layer. However, it should be appreciated that thefeatures described here can be applied to various other kinds ofdisplays so long as the display is equipped with a plurality ofconductive lines carrying signals from a driver of the display device isplaced under the array of TFTs and connected to an array of transparentelectrode blocks placed above the array of TFTs. That is, the featuresdescribed in the present disclosure can also be adopted in displaytechnologies other than the LCD display such as theorganic-light-emitting-diode (OLED) display.

For instance, in an OLED display, a plurality of conductive lines may beplaced on one side of the TFT array, and the conductive lines may beconnected to the array of transparent electrode blocks provided on theother side of the TFT array. The transparent electrode blocks providedon the other side of the TFT array may serve as a touch sensor toprovide touch recognition functionality. As mentioned, the functionalityof the array of transparent electrode blocks provided over the TFT arrayis not limited to the touch sensing, but may also be used for variousother functionalities such as touch-pressure sensing functionality,tactile feedback functionality and more. As such, it should be notedthat the term “transparent electrode blocks” and “common electrodeblocks” are used interchangeably in this disclosure.

[Exemplary Display Panel]

FIG. 2 schematically illustrates a configuration of a display panel PNLaccording to an embodiment of the present invention. Referring to FIG.2, the display panel PNL includes a plurality of display pixels P,connected to a plurality of data lines DL and a plurality of gate linesGL. A data driver DD and a data driver DD are provided in the areaoutside the display area, which may be referred to as the inactive area(i.e., non-display area). The data driver DD and the gate driver GD areconfigured to provide data signals and the gate signals on the datalines DL and the gate lines GL, respectively, to operate display pixelsP in the display area.

The pixels include electrodes or other capacitive elements may be usedfor display functionality and also for touch-sensing functionality. In aliquid crystal display, for instance, a layer of liquid crystalmolecules is interposed between two substrates, and the pixel electrodeand the common electrode provided on one of the two substrates areprovided with data voltage and the common voltage, respectively, togenerate electrical fields to control the amount of light passingthrough the layer of the liquid crystal molecules. The light passedthrough the liquid crystal layer also passes through the color filtersand a black matrix provided on one of the substrates to represent imageson the screen. In the display panel PNL depicted in FIG. 2, a commonelectrode VCOM is divided into a plurality of common electrode blocks(denoted with B1-B12). For simpler explanation, only B1-B9 are depictedin FIG. 2. However, the common electrode VCOM can be provided with morenumber of separated pieces of common electrode blocks.

Each of the display pixels P includes a thin-film-transistor (TFT) witha gate, a source and a drain. Each of the display pixel P includes acapacitor, which is formed with a pixel electrode PXL and the commonelectrode VCOM. The gate of the TFT is connected to a gate line GL, thesource of the TFT is connected to the data line DL and the drain of theTFT is connected to the pixel electrode PXL of the respective pixel.

The touch driver TD is configured to send and receive touch-sensingrelated signals to and from each of the common electrode blocks via aplurality of common signal lines SL to use the common electrode blocksin sensing touch inputs on the display panel PNL. It should beappreciated that a transparent electrode provided in the display panelPNL other than the common electrode VCOM may be divided into a pluralityof segmented blocks, and configured to send and receive touch-sensingrelated signals to and from the touch driver TD via a plurality ofcommon signal lines SL.

In an organic-light-emitting diode (OLED) display panel, a plurality ofseparated transparent electrode blocks arranged across the display areaof the OLED display panel can also be configured to communicate with thetouch driver TD via a plurality of common signal lines SL.

In some embodiments, all of the data driver DD, the gate driver GD andthe touch driver TD may be provided on a substrate of the display panelPNL. In some other embodiments, some of those drivers may be provided ona separate printed circuit board, which is coupled to the substrate ofthe display panel PNL via a suitable interface connection means (e.g.,pads, pins, etc.). Although each of the data driver DD, the gate driverGD and the touch driver TD is illustrated as a discrete component inFIG. 2, some or all of these drivers may be integrated with one anotherinto a single component. For instance, the touch driver TD may beprovided as a part of the data driver DD. In such cases, some of thetouch sense functionality related signals communicated between the touchdriver TD and the plurality of common electrode blocks may betransmitted via the data driver DD. Also, the data driver DD and thetouch driver TD may be provided on the same printed circuit board, whichis connected to the common signal lines SL and the data lines DLprovided on the substrate of the display panel PNL.

FIGS. 3A and 3B illustrate exemplary configurations of the transparentelectrode blocks (i.e., the common electrode blocks) and the wirings forthe transparent electrode blocks to implement a touch sensor in thedisplay panel PNL. In particular, FIG. 3A illustrates an exemplaryconfiguration of common electrode blocks (B1-B9) and the common signallines SL for a self-capacitance touch recognition system. In theself-capacitance touch recognition system, each common electrode blocks(B1-B9) function as a touch sense electrode with a unique coordinate,and thus change of capacitance read from each of the common electrodeblocks can be used to detect the location of the touch inputs on thedisplay panel PNL. To achieve this, each common electrode block isprovided with a discrete signal path to the touch driver TD, which isimplemented with the common signal line SL. That is, each common signalline SL is connected with just one common electrode block, although eachcommon electrode block may be connected with multiple common signallines SL, which forms a signal path between the common electrode blockand the touch driver TD.

FIG. 3B illustrates an exemplary configuration of common electrodeblocks (B1-B9) and the common signal lines SL for a mutual-capacitancetouch recognition system in the display panel PNL. Unlike theself-capacitance touch recognition system, the mutual-capacitance touchrecognition system relies on the changes in capacitance between a pairof touch-driving electrode and a touch-sensing electrode to detect thelocation of the touch inputs on the display panel PNL. Accordingly, in amutual-capacitance touch recognition system, the common electrode blocksare selectively grouped together so that some groups of common electrodeblocks serve as touch-driving electrodes and some other groups of commonelectrode blocks serve as touch-sensing electrodes. To this end, thecommon signal lines SL can be grouped together such that the groups ofcommon electrode blocks arranged in one direction (e.g., X-direction)collectively forms touch-driving electrodes (e.g., TX1-TX3), and groupsof common electrode blocks arranged in another direction (e.g.,Y-direction) collectively forms a touch-sensing electrodes (e.g., RX1).

The common signal lines SL connected to the corresponding ones of thecommon electrode blocks are routed directly across the active area(i.e., display area) of the display panel PNL, and they are groupedtogether at the outside of the active area to form either the TX linesor the RX lines. By way of an example, the common signal lines SL fromthe common electrode blocks B1 and B3 are grouped together asillustrated in FIG. 2B, so that the first touch-driving line TX1 isformed in X-direction. Similarly, the common signal lines SL from thecommon electrode blocks B4 and B6, and the common electrode blocks B7and B9 are grouped together to form touch-driving lines TX2 and TX3,respectively. The touch-sensing line RX is formed in Y-direction bygrouping the common signal lines SL from the common electrode blocks B2,B5 and B8. The TX lines TX1-TX3 may be oriented in in same direction asthe gate lines GL (e.g., X-Direction), and the touch-sensing line RX maybe oriented in the same direction as the data lines DL (Y-Direction). Inthis way, a mutual capacitance is formed at intersections between the TXlines and the Rx line.

In FIGS. 3A and 3B, only nine common electrode blocks are depicted forsimpler explanation. However, it should be understood that the number ofcommon electrode blocks provided in the display panel PNL is not limitedas such, and the common electrode of the display panel PNL can beadditional pieces of common electrode blocks. By way of a non-limitingexample, a display panel PNL may include 36×48 common electrode blocks.Also, it should be noted that the size of individual display pixel maybe much smaller than the size of an individual unit of touch senseregion to be provided in the display panel PNL. In other words, the sizeof each common electrode block can be larger than the size of eachindividual display pixel. Accordingly, a group of pixels can share asingle common electrode block, although each of those pixels is providedwith an individual pixel electrode. In a non-limiting example, a singlecommon electrode block may be shared by pixels arranged in 45 columns by45 rows (each pixel comprising a red, a green and a blue sub-pixel).

[Touch Scan Operation]

FIG. 4 shows exemplary signals applied through the common signal linesSL to the common electrode blocks during a display period and during atouch-sensing period according to an embodiment of the presentdisclosure. Since the common electrode blocks are also used as the touchelectrode, they are transmitted with signals related to displayfunctionality for a certain period and provided with touch sensingrelated signals for a certain period. That is, one frame period, whichis defined by the vertical sync signal, includes a display period and atouch-sensing period.

The display period may only be a part of one frame period. In thedisplay period, the gate signals and the data signals are provided onthe gate lines GL and the data lines DL, respectively, for charging thepixels with new image data. The remainder of the frame period can beused for preparing the pixels to receive the next image data as well asfor scanning the common electrode blocks for identifying touch inputs onthe screen. For instance, each frame is 16.6 ms when a display panelconfigured operated at a frequency of 60 frames per second. Within 16.6ms, about 12 ms can be dedicated for the display period. The rest can beused for carrying out the touch-sensing functionality and for preparingthe pixels to receive a new frame of image data.

Accordingly, the common voltage signal is transmitted from the datadriver DD to the common electrode blocks during the display period. Inthe touch scan period, the touch-driving signal is transmitted from thetouch driver TD to the common electrode blocks via the common signallines SL.

In some embodiments, the common voltage signal may be in the form of apulse signal that swings between a positive voltage and a negativevoltage to perform LCD inversion. In some embodiments, the commonvoltage signal is supplied to the common electrode blocks via the commonsignal lines SL. Alternatively, in some other embodiments, the commonvoltage signal may be supplied to the common electrode blocks viadedicated common voltage signal line SL other than the common signalline SL. Further, in some embodiments, the common signal lines SL mayserve as auxiliary means for supplying the common voltage signal to thecommon electrode blocks in addition to the signal lines dedicated forsupplying the common voltage signal to the common electrode blocks.

[Intra-Frame Pause Touch Scanning Scheme]

In some embodiments, the display panel PNL can be configured to performthe touch scan operation at least two times within a single frame. Thatis, the display period in a frame can be divided into at least twoseparate display periods, and an intermediate touch scan period can bepositioned in between two separate display periods of the same frame.FIG. 5A illustrates an exemplary Intra Frame Pause (IFP) driving scheme,which may be used in embodiments of the display panel PNL of the presentdisclosure. Accordingly, an intra-frame touch scan operation isperformed at least once in between two separate display periods of thesame frame, and at least once more during the blanking period before thenext frame starts. During the intermediate touch scan period positionedbetween the two separate display periods, scan signal is not provided onthe gate lines GL. Such a gate driving scheme may be referred to as the“intra-frame pause” (IFP) driving.

Referring to FIG. 5A, a frame includes a first display period and asecond display period, which are separated by an IFP touch scan period.A blanking period follows the second display period. During the firstdisplay period, scan signal is sequentially provided on the gate linesGL1 through GL(m). After the scan signal is supplied on the gate lineGL(m), the intra-frame touch scan operation begins on the display panelPNL. Supplying scan signal on the gate lines GL(m+1) through GL(end)resumes after the completion of the intra-frame touch scan operation.Once the scan signal is supplied on all of the gate lines GL, anothertouch scan operation is performed during the blanking period. Ifdesired, additional display period and additional intra-frame touch scanperiod can be provided within a single frame to increase the touch scanresolution of the display panel PNL.

In an example depicted in FIG. 5B, a display panel having 2048 gatelines GL may be driven at 120 Hz (120 frames per second). With 2048 gatelines, a single frame can include a first display period and a seconddisplay period, each of which is 1024H long. The IFP touch scan periodbetween the first display period and the second display period can be182H long, and the blanking period following the second display periodcan be 800H long.

In this example, the length of the first display period and the lengthof the second display period are the same. However, it should beappreciated that the length of the first display period and the lengthof the second display period can be different from each other. To put itin other term, the number of gate lines provided with the scan signalduring the first display period may be different from the number of gatelines provided with the scan signal during the second display period.

As will be described in further detail below, temporarily pausing thescan signal output on the same gate line for every frame can acceleratedeterioration of a specific part of the gate driver GD (e.g., specificstage of a shift register, specific transistor(s), etc.). Therefore, insome embodiments, the length of the first period and the length of thesecond period can change in between two different frames. By way of anexample, the first display period may be longer than the second displayperiod, during a first frame (i.e., more number of gate lines aresupplied with the scan signal during the first display period than thenumber of gate lines supplied with the scan signal during the seconddisplay period). In a second frame, the first display period may beshorter than the second display period (i.e., less number of gate linesare supplied with the scan signal during the first display period thanthe number of gate lines supplied with the scan signal during the seconddisplay period).

In cases where the common electrode blocks are configured as theself-capacitance touch recognition system, each of the common electrodeblocks are provided with touch-driving pulses, and the signals from eachof the common electrode blocks are analyzed to determine whether a touchinput was registered on a particular common electrode block. Morespecifically, in the self-capacitive touch recognition system, chargingor discharging of the touch-driving pulse on the common electrode blockscan be used to determine touch inputs on the common electrode blocks.For example, a change in the capacitance value upon a touch inputchanges the time in which the voltage slopes on the common electrodeblock. Such a change on each of the common electrode blocks can beanalyzed to determine the location of touch input on the display panelPNL.

In cases where the common electrode blocks are configured as themutual-capacitance touch recognition system, groups of common electrodeblocks that are configured as the touch-driving lines (TX) are providedwith the touch-driving pulses, and groups of common electrode blocksthat are configured as the touch-sensing lines (RX) are provided with atouch reference voltage signal. A touch input made on the display panelPNL changes the capacitive coupling at the intersection of the touchdriving line (TX) and the touch sensing line (RX), and it changes thecurrent that is carried by the touch sensing line (RX). This informationin a raw or in some processed form can be used to determine thelocations of touch inputs on the display panel PNL. The touch driver TDperforms this operation for each intersections of the TX and RX lines atrapid rate so as to provide multipoint sensing.

In the example shown in FIG. 3B, each of the TX lines was defined by agroup of common electrode blocks arranged in a row (X-direction), andeach of the RX lines was defined by a group of common electrode blocksarranged in a column (Y-direction). The number of TX and RX lines in thedisplay panel PNL can be adjusted according to the arrangement and sizesof the common electrode blocks in in the active area.

The arrangement of the common electrode blocks is not limited asdepicted in FIG. 3B, and may be arranged in a various other waysdepending on the desired layout of the TX and RX lines in the displaypanel PNL. The number of TX lines implemented with the common electrodeblocks arranged in a single row as well as the number of RX linesimplemented with the common electrode blocks arranged in a single columncan vary depending on various factors. For instance, the commonelectrode blocks arranged in a single row can be used to providemultiple TX lines, and the common electrode blocks arranged in a singlecolumn can be used to provide multiple RX lines based on the touchscanning frequency and the accuracy as well as the size of the displaypanel PNL.

Also, the RX line in the mutual-capacitance touch recognition system canbe formed with a common electrode block that is larger than the commonelectrode blocks forming the TX lines. For instance, rather than formingan RX line with a plurality of common electrode blocks arranged incolumn direction, a single large common electrode block that extendsacross the active area in the column direction (i.e., Y-direction) canbe used as a RX line.

In order to improve the touch-sensing accuracy at the edges of thedisplay panel PNL, the common signal lines SL from the common electrodeblocks positioned at each of the far most ends of the active area (i.e.,left and right ends) can be grouped together such that RX lines areformed at the far most ends of the active area. In this way, touchinputs made by the object with a very smaller touch point (e.g., 2.50)than a typical size of a finger can be recognized at the edges of thedisplay panel PNL.

To further improve the performance of the touch-sensing capability, thewidth of the common electrode blocks that serve as the RX lines at thefar most end of the display panel PNL may be different from the width ofother touch-sensing blocks in the other areas of the display panel PNL.

Configuring the common electrode blocks at the farthest ends of thedisplay panel PNL as an RX line allows for more accurate touch inputrecognition even from the very end portions of the active area. However,this means that the location of the common electrode blocks that serveas the TX line will shift away from the edges by the width of the commonelectrode blocks serving as the RX line at the edges. Also, each TX linedoes not fully extend across the RX lines positioned at the edges.Accordingly, the width of the common electrode blocks at the edges maybe narrower than the width of the common electrode blocks at other areasof the active area. For instance, the width of the common electrodeblocks, measured in X-direction, at the edges of the active area may be½ of common electrode blocks positioned elsewhere.

To improve the touch-sensing accuracy at the upper and lower edges ofthe display panel PNL, the common electrode blocks at the upper andlower edges of the display panel PNL can have a reduced width, measuredin Y-direction, as compared to other common electrode blocks atdifferent areas of the display panel PNL. This way, narrower TX linescan be provided at the top and bottom edges of the display panel PNL.

Regardless of which type of touch recognition system is implemented inthe display panel PNL, each of the common electrode blocks are connectedwith at least one common signal line SL. The common signal lines SLextend parallel to one another and routed outside the active area in thesame direction as the data lines DL. Arranging the common signal linesSL parallel to each other and having them routed across the active areatoward the drivers allows to eliminate needs for a space in thenon-display area of the display panel for routing the common signallines SL, and thereby reducing the size of the bezel.

Each common signal line SL connected to a corresponding common electrodeblock runs across the active area of the display panel PNL toward thenon-display area, bypassing common electrode blocks that are connectedother common signal lines. For instance, the common signal line SLconnected to the common electrode block B1 is routed across underneaththe common electrode blocks B4 and B7 to reach the non-display areawhere the drivers are located without being in contact with the commonelectrode blocks B4 and B7 in the route.

The common signal lines SL cannot be positioned immediately on thesurface of the common electrode blocks. If the common signal lines SLare routed on the surface of the common electrode blocks, the commonsignal lines SL will be in contact with multiple common electrode blocksalong path toward the non-display area. This will disrupt the uniquecoordinates of the common electrode blocks in the self-capacitance touchrecognition system or break the formation of TX/RX lines in themutual-capacitance touch recognition system.

Also, when the common signal lines SL are positioned in the same layeras the pixel electrode PXL, coupling generated between the common signallines SL and the pixel electrode PXL may cause various display defectswhen the common signal lines SL are used to modulate the commonelectrode blocks during the touch-sensing period. Accordingly, placingthe common signal lines SL in the same layer as the pixel electrodes PXLmakes it difficult to reduce the space between the common electrodeblocks and the pixel electrode PXL, resulting in lower storagecapacitance. Further, unwanted fringe field may be generated when thecommon signal lines SL are placed in either the common electrode layeror the pixel electrode layer. Such fringe field can affects the liquidcrystal molecules and lead to undesired light leakage. Thus, in order toroute the common signal lines SL across the active area of the displaypanel PNL, the plane level of the common signal lines SL should bedifferent from the plane levels of the pixel electrode and the commonelectrode blocks.

Placing the common signal lines SL between the layer of pixel electrodeand the layer of common electrode blocks poses similar problems. In sucha configuration, an insulation layer should be provided between thelayer of the common electrode blocks and the layer of common signallines SL. The thickness of the insulation layer interposed between thepixel electrode and the common electrode blocks is limited in the IPS orthe FFS mode LCD device, and it also limits the thickness of the commonsignal lines SL as it cannot be greater than the thickness of theinsulation layer between the layer of pixel electrodes and the layer ofcommon electrode blocks.

For instance, when the thickness of the insulation layer interposedbetween the pixel electrode and the common electrode blocks is about3000 Å, the thickness of the common signal lines SL is limited to about2500 Å if the common signal lines SL are to be placed between the commonelectrode blocks and the pixel electrode. Since the thickness is one ofthe factors affecting the resistance of the common signal lines SL, thelimitation as to the thickness of the common signal lines SL effectivelylimits the performance of the common signal lines SL in transmittingsignals between the driver and the common electrode blocks, especiallyas the size of the display area in the device becomes larger.

For the reasons stated above, the common signal lines SL are positionedunder the array of TFTs such that they are sufficiently distanced awayfrom the pixel electrode and the common electrode blocks provided abovethe array of TFTs. Such a setting provides more leeway in increasing thewidth and thickness of the common signal lines SL. To this end, one ormore planarization layer is provided between the common signal lines SLand the common electrode blocks, and the common signal lines SL areconnected to the corresponding common electrode blocks via contact holesthrough the planarization layer. In such settings, each of the commonsignal lines SL connected to a common electrode block can be routedacross the active area without contacting other common electrode blocksplaced along its route. The common signal lines SL can simply bypass thecommon electrode blocks along the path to the touch driver TD in theinactive area.

[Bypass Lines]

In some embodiments, the common signal lines SL are connected to thecorresponding common electrode blocks via bypass lines, which areconnected to both the common signal lines SL and the common electrodeblocks through the contact holes in the planarization layers.

FIG. 6A is a top view of an exemplary configuration of the common signallines SL and the bypass lines BL in a matrix of pixel regions in thedisplay panel PNL, according to an embodiment of the present disclosure.Referring to FIG. 6A, the data lines DL and the gate lines GL arearranged to intersect each other, thereby defining a matrix of pixelregions in the display area of the display panel PNL. The common signallines SL are arranged to extend in the same direction as the data linesDL. Each common signal line SL is positioned to at least partiallyoverlap with a data line DL to minimize reduction in the aperture ratioof the pixel regions by the common signal lines SL. As will be describedbelow, a dummy line DML may be placed underneath some of the data linesDL in place of the common signal line SL.

Each pixel region is provided with a TFT. The TFT may be formed in thebottom gate structure with the source and drain provided on the oppositeside of the semiconductor layer SEM. Such TFT structure is sometimesreferred to as the inverted staggered structure or the back-channeletched structure. The source electrode of the TFT extends from orotherwise connected to the data line DL, and the drain is connected tothe pixel electrode PXL (not shown in FIG. 6A) provided in thecorresponding pixel region. The pixel electrode PXL is provided with aplurality of slits to generate electrical field in conjunction with theoverlapping common electrode block (not shown).

The common signal lines SL are placed under the TFTs of the pixels, andeach of the common electrode blocks is connected to the ones of thecorresponding common signal lines SL via contact holes (i.e., lowercontact hole: CTL; upper contact hole: CTU) through the planarizationlayers formed over the TFTs. In this configuration, each common signalline SL is connected to at least one bypass line BL that is connected tothe corresponding common electrode block.

The bypass line BL may be arranged in the same direction as the gateline GL such that a bypass line BL extends across from one pixel regionto another pixel region of the same row. That is, the connection betweenthe bypass line BL and the common signal line SL can be made via acontact hole provided in one pixel region, and the connection betweenthe bypass line BL and the common electrode block can be made via acontact hole provided in another pixel region. As shown in FIG. 6A,usable aperture ratio in the pixel regions vary due to the bypass linesBL and the contact holes (CTL, CTU) for connecting the common signallines SL and the common electrode blocks to the bypass lines BL.

FIG. 6B is a cross-sectional view showing an exemplary configuration forconnecting a common signal line to a common electrode block via a bypassline BL. FIG. 6C illustrates the order in which the metal layers aredisposed over one another to form the common signal lines SL, the bypasslines BL, the gate lines GL, the data lines DL and the source/drain ofthe TFT in the display panel PNL. In the present disclosure, the metallayer is referred in accordance with the order in which each of themetal layers is placed on the substrate.

Referring to FIGS. 6B and 6C, the common signal lines SL are formed withthe first metal layer on the substrate. The metal layer used in formingthe common signal lines SL is referred to as the first metal layer M1 asit is first metal layer disposed on the substrate, and for convenienceof explanation, other metal layers on the first metal layer M1 arereferred to as the second metal layer M2, the third metal layer M3 andso forth in the order from the first metal layer M1. The second metallayer M2 may be referred to as the gate metal layer and the third metallayer M3 may be referred to as the source/drain metal layer.

It should be noted that the term “first metal layer” do not necessarilymean that the layer is comprised of a single metal layer. Instead, theterm “first metal layer” refers to a metal layer or a stack of metallayers capable of being patterned on a surface and insulated fromanother layer of metal layer or another stack of metal layers by aninsulation layer. Similar to the first metal layer M1, other subsequentmetal layers (e.g., the second metal layer M2, the third metal layer M3)in the embodiments of the present disclosure may be formed of a stack ofmultiple layers of different metals.

The metal layers forming the common signal lines SL, gate lines GL,bypass lines BL, and data lines DL may be formed of a stack of metallayers such as copper, molybdenum, titanium, aluminum and thecombination thereof. In a suitable embodiment, the first metal layer M1may be formed of a stack of a copper layer (Cu) and amolybdenum-titanium alloy layer (MoTi). The second metal layer M2 mayalso be a stack of a copper layer (Cu) and a molybdenum-titanium alloylayer (Mori). The third metal layer M3 may be a stack of amolybdenum-titanium alloy layer (Moti), copper layer (Cu) and anothermolybdenum-titanium alloy layer (Moti). The copper layer may be thickerthan the molybdenum-titanium alloy layer in each of the metal layers.

[Lower Planarization Layer]

To provide an array of TFTs on the common signal lines SL, a lowerplanarization layer PLN-L is provided over the common signal lines SL.The thickness of the lower planarization layer PLN-L may vary dependingon the thickness of the common signal lines SL. For example, thethickness of the common signal lines SL may range from about 2500 Å toabout 7500 Å, and more preferably from about 3500 Å to about 6500 Å, andmore preferably from about 4500 Å to about 5500 Å. In one particularexample, the common signal lines SL are patterned from the first metallayer M1 formed of a stack of a copper layer (Cu) and amolybdenum-titanium alloy layer (MoTi), the thickness of the copperlayer can be ranged from about 4500 Å to about 5500 Å and the thicknessof the molybdenum-titanium alloy layer (MoTi) can be ranged from about100 Å to about 500 Å.

The thickness of the lower planarization layer PLN-L covering the commonsignal lines SL may range from about 0.5 μm to 4 μm, and more preferablyfrom about 0.5 μm to 3 μm, and more preferably from about 0.5 μm to 2μm. The thickness of the planarization layer that covers the commonsignal lines SL can vary based on various factors, such as thedielectric property, material, fabrication process, and more.

The array of TFTs is fabricated on the lower planarization layer PLN-L.It should be noted that fabrication of TFTs involves high-temperatureprocesses and chemical treatments. The upper planarization layer PNL-Uplaced on the TFTs is not directly affected by the processes andtreatments involved in fabrication of the TFTs. On the other hand, thelower planarization layer PNL-L, which is provided under the TFTs, isdirectly affected by the processes and treatments performed duringfabrication of the TFTs, electrodes and other components on the lowerplanarization layer PNL-L.

Accordingly, the lower planarization layer PNL-L should have sufficientthermal stability, mechanical stability, chemical endurance andresistance to photoresist strippers/developers so that the lowerplanarization layer can withstand processes and treatments performed informing the array of the TFTs, electrodes and various other componentsimplementing the pixel circuitry.

For example, some of the processes during the fabrication TFTs with anoxide semiconductor layer, such as IGZO (indium-Gallium-Zinc-Oxide), maybe carried out at about 350 degrees Celsius or higher. Fabrication ofTFTs with a poly-silicon semiconductor layer may require a processperformed at even a higher temperature. As such, the lower planarizationlayer PLN-L cannot be formed of photo-acryl, which is generally used asthe planarization layer covering the TFTs. Instead, the lowerplanarization layer PLN-L may be formed of a material exhibiting asufficient thermal stability to cover the common signal lines SL and toprovide a planar surface for the TFTs to be fabricated thereon, whilesustaining the physical structure and the optical property to be used ina display panel PNL.

In particular, the lower planarization layer PLN-L should maintain aplanar surface over the common signal lines SL at a temperature equal toor greater than 350 degrees Celsius. More preferably, the lowerplanarization layer PLN-L may maintain a planar surface over the commonsignal lines SL at a temperature equal to or greater than 380 degreesCelsius. To put it in another term, the lower planarization layer PLN-Nmay include a material, which exhibits less than 1% of thermalgravimetric analysis (TGA; isothermal) at 350 degrees Celsius for 30minutes (% weight loss at 350 C/30 min). More preferably, the lowerplanarization layer PLN-N may include a material, which exhibits lessthan 0.1% of TGA at 380 degrees Celsius for 30 minutes.

The lower planarization layer PLN-L should exhibit suitable opticalproperties, even following the processes and treatments involved duringthe fabrication of TFTs. This is especially true for a LCD panel as thelight emitted from the light source would pass through the lowerplanarization layer PNL-L. In this regard, the average lighttransmittance rate of the lower planarization layer PNL-L may be greaterthan 70%, more preferably greater than 80%, and more preferably greaterthan 90% (% measured for 400-800 nm thickness on a bare glass). Further,the refractive index of the material for forming the lower planarizationlayer PNL-L may have a refractive index ranged from 1.4 to 1.6. In aparticular example, a bare glass coated with the lower planarizationlayer PNL-L in a thickness of 400 nm exhibited average lighttransmittance of about 91.24%˜91.25%, even after being placed at 380 Cfor 30 minutes. Also, the lower planarization layer PNL-L exhibited arefractive index of 1.49 at 633 nm thickness.

The lower planarization layer PNL-L should also exhibit sufficientchemical endurance to withstand the chemical treatments duringfabrication of TFTs, electrodes and other components on the lowerplanarization layer PNL-L. For instance, the lower planarization layerPNL-L may exhibits sufficient chemical endurance against deionized water(DI), isopropyl alcohol (IPA), propylene glycol methyl ether acetate(PGMEA) and the like. In a particular example, the thickness of a lowerplanarization layer PNL-L (e.g., 1.3 um) may change less than 10angstroms when treated with DI water or IPA (at 70 C/10 min), and maychange less than 20 angstroms when treated with PGMEA (at RT/10 min).

The lower planarization layer PNL-L should also have sufficientresistance to photoresist strippers/developers used in fabrication ofTFTs, electrodes and other components on the lower planarization layerPNL-L. In a particular example, the thickness of a lower planarizationlayer PNL-L (e.g., 1.3 um) may change less than 10 angstroms whentreated with N-Methyl-2-pyrrolidone (NMP) (at 70 C/10 min), and maychange less than 20 angstroms when treated with 2.38%tetra-methyl-ammonium hydroxide (TMAH) (at RT/10 min).

In some embodiments, the lower planarization layer PNL-L is formed of anorganosiloxane hybrid layer based on Si—O monomer and polymer. In thepresent disclosure, the hybrid polysiloxane polymer layer may be simplyreferred to as a SOG layer.

In embodiments where the lower planarization layer PNL-L is formed of aSOG layer, the lower planarization layer may include a hybridpolysiloxane polymer layer, where the hybrid polymer contains organiccontents, which includes alkyl and aryl functionalities, as expressed inthe chemical formula

1 below.(n and m refer to number of repeating units)

The material for forming the lower planarization layer PNL-L (e.g., SOGlayer) should also be suitable for spin-on-glass method, slit coatingmethod, slot-die coating method or other suitable coating methods tocover and to provide planar surface on the common signal lines SL. Insome embodiments, viscosity profile of the material that forms the lowerplanarization layer PNL-L is in a range between 2.5 cps to 3 cps at 25C, and more preferably in a range between 2.5 cps to 2.7 cps at 25 C.The density of the material that forms the lower planarization layerPNL-L may be about 1.0 g/ml at 25 C. Curing process may be performedonce the lower planarization layer PNL-L is coated over the commonsignal lines SL.

Metallic ions from the first metal layer M1, which forms the commonsignal lines SL, may be diffused into the lower planarization layerPLN-L by the heat from the curing process of the lower planarizationlayer PLN-L and/or the annealing processes involved in TFT fabrication.Similarly, metallic ions from the second metal layer M2, which forms thegate lines GL and the bypass lines BL, may also be diffused into thelower planarization layer PLN-L by the heat involved duringcuring/annealing processes. For instance, Cu diffusion into the lowerplanarization layer can occur when either the first metal layer M1 orthe second metal layer M2 includes copper (Cu). Furthermore, metallicion impurities and/or moisture from the glass substrate may also bediffused into the lower planarization layer PLN-L. Such metallic ionsand other impurities diffused into the lower planarization layer PLN-Lcan increase the permittivity of the lower planarization layer PLN-L,which in turn increases resistance-capacitance (RC) delay time thathampers the touch sensing performance of the display panel PNL.

Accordingly, in some embodiments, a passivation layer PAS1, serving as acapping layer, is provided under the lower planarization layer PLN-L. Insuch embodiments, the passivation layer PAS1 covers the common signallines SL and the surface of the substrate. Not only does the passivationlayer PAS1 block metallic ions and other impurities from the commonsignal lines SL and the substrate, it also improves adhesion of thelower planarization layer PLN-L on the substrate. Further, in someembodiments, a passivation layer PAS2 may be provided on the lowerplanarization layer PLN-L. In this case, the passivation layer PAS2 isinterposed between the lower planarization layer PLN-L and the secondmetal layer M2 (e.g., gate lines GL, bypass lines BL) to suppressdiffusion from the second metal layer M2.

The passivation layer PAS1 and PAS2 may be a silicon nitride layer, asilicon oxide layer or stacks of such layers. In some suitableembodiments, the passivation layer PAS1 under the lower planarizationlayer PLN-L and the passivation layer PAS2 on the planarization layerPLN-L may be provided in a substantially the same thickness, and may beformed of the same inorganic material. For instance, both thepassivation layer PAS1 and the passivation layer PAS2 may be a siliconnitride layer with a thickness between about 1000 Å and about 3000 Å. Insome suitable embodiments, the lower planarization PLN-L having athickness of 17,000 Å can be provided with the passivation layer PAS1and the passivation layer PAS2, each with a thickness of about 2000 Å.

Not only does the passivation layer PAS2 serve as a capping layer, itcan also provide protection for components that are placed on the lowerplanarization layer PLN-L from undesired fumes (e.g., hydrogen fumes)from the lower planarization layer PLN-L. As such, the material andconfiguration of the passivation layer PAS2 between the lowerplanarization layer PLN-L and the array of TFT can vary depending on thesemiconductor layer (i.e., active layer) of the TFTs on the lowerplanarization layer PLN-L. For example, in some embodiments, thepassivation layer PAS2 may be formed of a silicon nitride layer when theTFTs above uses oxide metal semiconductor (e.g., IGZO). It should benoted that, in some embodiments, the passivation layer PAS2 may not beprovided between the lower planarization layer PLN-L and the conductivelines of the second metal layer M2, for instance the gate lines GL andthe bypass lines BL.

With the common signal lines SL covered under the lower planarizationlayer PLN-L, the gate lines GL and the gates G of the TFTs are patternedwith the second metal layer M2 on the lower planarization layer PLN-L.The bypass lines BL are also patterned from the second metal layer M2provided on the lower planarization layer PLN-L. The semiconductor layer(e.g., oxide, LTPS, a-Si) is patterned on the gate insulation layer GIto provide the TFT's channel ACT. The data line DL, which is connectedto the source S of the TFT, is formed with the third metal layer M3.

To provide a planar surface for placing the common electrode blocks, theupper planarization layer PLN-U is provided over the TFTs and the bypasslines BL. The drain D of the TFT is in contact with the pixel electrodePXL through a contact hole in the upper planarization layer PLN-U. Asshown, a passivation layer PAS3 formed of inorganic material, such asSiNx and/or SiOx, may be interposed between upper planarization layerPLN-U and the third metal layer M3. Another passivation layer, PAS4, isinterposed between the common electrode blocks and the pixel electrodesPXL provided on the upper planarization layer PLN-U.

A contact bridge may be present at upper contact hole CTU for connectinga bypass line BL and the corresponding common electrode block. Morespecifically, the contact bridge is patterned from the third metal layerM3 on the contact region of the bypass line BL (i.e., BL-VCOM contactregion), and is exposed through the upper contact hole CTU in the upperplanarization layer PLN-U.

Each one of the common signal lines SL is connected to one of the commonelectrode blocks by one or more bypass lines BL. In this regard, one endof a bypass line BL is connected to the common signal line SL via alower contact hole CTL through the lower planarization layer PLN-L atthe SL-BL contact region. The other end of the bypass line BL isconnected to the common electrode block via the upper contact hole CTUthrough the upper planarization layer PLN-U at the BL-VCOM contactregion. As depicted in FIG. 6B, a contact bridge formed of the samemetal layer as the source/drain metal of the TFT (i.e., the third metallayer M3), may be interposed between the bypass line BL and the commonelectrode block. The common electrode block can come in contact with thecontact bridge through the upper contact hole CTU so as to electricallyconnect the common electrode block and the bypass line BL. However, itshould be noted that the contact bridge is not necessary to provide theconnection between the bypass line BL and the common electrode block. Assuch, in some other embodiments, the bypass line BL may directly contactthe common signal line SL through the lower contact hole CTL without thecontact bridge interconnecting them.

Each common signal line SL includes a routing portion extending under adata line DL and a contact portion projecting out from the routingportion toward the lower contact hole CTL. The end of the contactportion at the SL-BL contact region may be enlarged to ensure thecontact area size through the lower contact hole CTL. Likewise, the endsof the bypass line BL corresponding to the SL-BL contact region and theBL-VCOM contact region may be wider than the interim section of thebypass line BL. Although only one of the common signal line SL isdepicted with the contact portion in FIG. 6C, contact portions of othercommon signal lines SL may be placed in pixel regions of different rows.

[Exemplary Manufacturing Steps/Masks]

FIGS. 7A and 7B illustrate an exemplary manufacturing method for a TFTsubstrate of a display panel PNL, according to an embodiment of thepresent disclosure. Referring to FIGS. 7A and 7B, in step 1, the firstmetal layer M1 is disposed on the lower substrate and is patterned toform the common signal lines SL on the lower substrate. Although notshown here, the first metal layer M1 may be patterned to form conductivelines and/or pads in the non-display area of the display panel PNL, ifdesired.

In step 2, the lower planarization layer PLN-L is disposed on the commonsignal lines SL. As shown, the passivation layer PAS1 may be provided oncommon signal lines SL and on the surface of the lower substrate. Alower contact hole CTL is formed at the SL-BL contact region where theconnection between the common signal line SL and a bypass line BL is tobe made. As such, a connection portion of a common signal line SL isexposed through the lower contact hole CTL at the SL-BL contact region.

If desired, some part of the lower substrate in the non-display area maynot be covered by the lower planarization layer PLN-L. For instance, insome embodiments, drivers (e.g., gate driver GD, data driver DD, touchdriver TD), metal traces (e.g., metal lines and pads) for connectingflexible printed circuit boards (FPCB) in the non-display area may beplaced on the lower substrate without being covered under the lowerplanarization layer PLN-L.

Curing process may be performed once the lower planarization layer PNL-Lis coated over the common signal lines SL. As the curing temperatureincreases, the coefficient of thermal expansion (CTE) for the lowerplanarization layer PLN-L (e.g., the SOG layer) decreases. The lowerplanarization layer PLN-L may deteriorate when cured at a temperaturethat causes decomposition of Si—O bonding. Also, the hardness and themodulus of the lower planarization layer PLN-L increase as the curingtemperature is raised, which can make the lower planarization layerPLN-L prone to cracks. As such, in suitable embodiments, the curingtemperature may be in a range between 350 C and 400 C. However, itshould be appreciated that the curing temperature is not limited assuch, and can vary depending on the material of the lower planarizationlayer PLN-L.

In step 3, the second metal layer M2 is patterned on the lowerplanarization layer PLN-L to form the gate lines GL and the bypass linesBL. Similar to the first metal layer M1, the second metal layer M2 mayalso be patterned to form metal traces in the non-display area, whichmay be arranged to be in contact with the metal traces patterned fromthe first metal layer M1. If the lower planarization layer PLN-L existsin the non-display area between the metal traces of the first metallayer M1 and the second metal layer M2, they may come in contact viacontact holes through the lower planarization layer PLN-L.

As mentioned above, a passivation layer PAS2 may be provided on thelower planarization layer PNL-L before placing the gate lines GL and thebypass lines BL. In some embodiments, the lower contact holes CTL forconnecting the common signal lines SL and the bypass lines BL may beformed after the passivation layer PAS2 is placed on the lowerplanarization layer PLN-L.

Alternatively, in some other embodiments, the lower contact holes CTL atthe SL-BL contact regions may be formed prior to forming the passivationlayer PAS2 on the lower planarization layer PLN-L for enhancedprotection against hydrogen fume (H+) from the lower planarization layerPLN-L. More specifically, the lower contact holes CTL can be formedbefore placing the passivation layer PAS2 on the lower planarizationlayer PLN-L. In this way, the passivation layer PAS2 is placed on thelower planarization layer PLN-L with the contact hole already formedtherein, and thus the side wall surface within the lower contact holesCTL can be covered by the passivation layer PAS2.

It should be noted that there may be free/unbound hydrogen (H) speciesin the passivation layer PAS2 (e.g., Si₃N₄) as well. Such hydrogenspecies may hamper the TFT performance, especially if the TFT to beplaced on the lower planarization layer PLN-L includes TFTs with oxidemetal semiconductor (e.g., IGZO). As such, in embodiments in which thepassivation layer PAS2 is present on the lower planarization layerPLN-L, the curing process may be performed after forming the passivationlayer PAS2 on the lower planarization layer PLN-L. In this way, thefree/unbound hydrogen (H) species in the passivation layer PAS2 can bereduced during the curing process.

In step 4, a gate insulation layer GI is provided on the gate lines GLand the bypass lines BL. On top of the gate insulation layer GI, asemiconductor layer SEM (e.g., IGZO) is disposed. Then, a contact holeis formed through the gate insulation layer GI and the semiconductorlayer SEM to expose a part of the bypass line BL at the BL-VCOM contactregion.

In step 5, the third metal layer M3 is disposed over the semiconductorlayer SEM, and is patterned along with the semiconductor layer SEM toform the data lines DL and source/drain of the TFTs. Accordingly, thesemiconductor layer SEM under the source/drain of the TFTs as well asunder the data lines DL remains intact even after the patterning of thethird metal layer M3.

The bypass line BL at the BL-VCOM contact region can be damaged duringpatterning of the third metal layer M3. As such, the photoresist may beremained on the BL-VCOM contact region during patterning of the thirdmetal layer M3. As a result, the third metal layer M3 under thephotoresist at the BL-VCOM contact region remains intact on the bypassline BL as depicted in FIG. 7A. In this case, electrical connectionbetween the bypass line BL and the common electrode block is made viathe piece of third metal layer M3 remaining at the BL-VCOM contactregion, which is referred in the present disclosure as the contactbridge.

In step 6, another passivation layer PAS3 is formed on the source/drainof the TFTs and the data lines DL. Then, the upper planarization layerPNL-U is provided on the passivation layer PAS3 to provide a planarsurface over the TFTs and the data lines DL. As the upper planarizationlayer PNL-U is provided on top of the TFTs and the data lines DL, thethermal stability of the material forming the upper planarization layerPLN-U need not be as great as the material of the lower planarizationlayer PLN-L. Accordingly, the upper planarization layer PLN-U may beformed of photo-acryl. The upper contact holes CTU are formed throughthe upper planarization layer PLN-U, exposing the passivation layer PAS3at the drain region of the TFTs and at the BL-VCOM contact region.

In step 7, the passivation layer PAS3 at the BL-VCOM contact region isremoved to expose the contact bridge at the BL-VCOM contact region.Here, the passivation layer PAS3 at the SD-PXL contact region of the TFTmay remain in the upper contact hole CTU.

In step 8, a transparent conductive layer, such as indium-tin-oxide(ITO) layer is formed on the upper planarization layer PLN-U to serve asthe common electrode VCOM of the display panel PNL. As described above,the common electrode VCOM is patterned into a plurality of separatedpieces, i.e., common electrode blocks.

In step 9, yet another passivation layer PAS4 is provided on the commonelectrode blocks and on the upper planarization layer PLN-U. Thepassivation layer PAS4 may also cover the surfaces inside the contactholes. For instance, passivation layer PAS4 may cover the passivationlayer PAS3 exposed under the upper contact hole CTU at the SD-PXLcontact region, the part of the common electrode block in the uppercontact hole CTU at the BL-VCOM contact region as well as the conductivelines/pads in the non-display area. Afterward, the passivation layerPAS4 can be etched at the selective regions to expose the surfacethereunder. As shown, the passivation layer PAS4 can be etched alongwith the passivation layer PAS3 inside the upper contact hole CTU at theSD-PXL contact region to expose the drain of the TFT.

In step 10, another transparent conductive layer (e.g., ITO) is disposedon the passivation layer PAS4, and is patterned to form the pixelelectrodes PXL. As the SD-PXL contact region of the TFT is exposed, thetransparent conductive layer comes in contact with the drain of the TFT.If desired, the transparent conductive layer can be disposed on theconductive lines/pads positioned in the non-display area as well.

In some embodiments, the common signal lines SL may be in direct contactwith the corresponding common electrode blocks. Since the common signalline LS is directly connected to the corresponding common electrodeblock without using the bypass line BL, any side effects which mayresult from using the bypass line BL (e.g., aperture ratio loss in thepixels) can be resolved.

[Common Signal Line-Transparent Block Direct Contact]

FIG. 8A illustrates an exemplary configuration of the common signal lineSL and the common electrode block, which are directly contacting eachother through the upper planarization layer PLN-U and the lowerplanarization layer PLN-L. Considering the step coverage of the commonelectrode block (e.g., ITO), the contact hole CT becomes narrower fromthe top to bottom toward the common signal line SL so that the commonelectrode block can reach the common signal line SL without adisconnection. More specifically, the upper part U of the contact holeCT at the upper planarization layer PLN-U can be wider than the mid partM of the contact hole CT at the passivation layer PAS3 and the gateinsulation layer GI. Further, the mid part M of the contact hole CT atthe passivation layer PAS3 and the gate insulation layer GI can be widerthan the lower part L of the contact hole CT at the lower planarizationlayer PLN-L. In some embodiments, the part of the contact hole at thegate insulation layer GI may be wider than the part of the contact holeat the passivation layer PAS3. In a suitable embodiments, the width D₂of the contact hole CT at the gate insulation layer GI and thepassivation layer PAS3 may be wider than the width D₃ of the contacthole CT at the lower planarization layer PLN-L by at least 2 um or more.

Also, the gate insulation layer may have a ledge in the contact hole CT.The ledge is formed in the contact hole CT when a part of the gateinsulation layer GI is etched in a first round of etching process andanother part of the gate insulation is etched in a second round ofetching processes different from the first round of the etching process.The first round of etching process can form the contact hole through thepassivation layer PAS3 and only a part of the gate insulation layer GI,leaving the gate insulation layer GI still covering the lowerplanarization layer PLN-L in the contact hole. Then, another round ofetching process is carried out to form the contact hole completelythrough the gate insulation layer GI, which will leave a ledge of a gateinsulation layer in the contact hole CT.

Manufacturing method is as follows. In step 1, a plurality of commonsignal lines SL are patterned on a substrate from the first metal layerM1. In step 2, the common signal lines SL are covered by the lowerplanarization layer PLN-L, which is followed by curing of the lowerplanarization PLN-L. Similar to the previous example which uses thebypass line BL, the passivation layer PAS1 and PAS2 may be provided onthe lower and upper surfaces of the lower planarization layer PLN-L,respectively. In step 3, the second metal layer M2 is patterned toprovide the gate lines GL and the gate electrode on the lowerplanarization layer PLN-L, which is followed by the deposition of thegate insulation layer GI. In step 4, the semiconductor layer SEM isdeposited on the gate insulation layer GI, and an annealing process isperformed. Then, the semiconductor layer SEM is patterned. In step 5,the third metal layer M3 is patterned to provide source/drain electrodesof the TFT and the data lines DL. In step 6, another passivation layerPAS3 is provided on the source/drain electrode and the data lines DL,then another annealing process is performed. In step 7, the upperplanarization layer PLN-U is deposited to provide a planar surface overthe TFTs, and the contact hole CT is formed through the upperplanarization layer PLN-U to open the SL-VCOM contact region.

FIG. 8B is schematic illustrations for explaining an exemplarymanufacturing method of a display panel PNL, in which the common signallines SL and the common electrode blocks are in direct contact with eachother. Referring to FIG. 8B, the photoresist PR can be provided over theupper planarization layer PLN-U as depicted in (A) of FIG. FIG. 8B. Thena photo/develop process is carried out to create a contact hole throughthe passivation layer PAS3 and the gate insulation layer GI. It shouldbe appreciated that the gate insulation layer GI may need to be providedat some part of the display panel PNL at least temporarily duringmanufacturing. For instance, the gate insulation layer GI may providetemporary protection for the metal trace lines in the non-display areaof the display panel PNL. In such cases, the gate insulation layer GImay remain on the SL-VCOM contact region. For instance, the passivationlayer PAS3 may be over etched, but not as much as to expose the surfaceof the lower planarization layer PLN-L, as depicted in (B) of FIG. FIG.8B.

After forming the contact hole through the passivation layer PAS3 andthe gate insulation layer GI, another photoresist deposition anddevelopment process can be carried out, and the lower planarizationlayer PLN-L at the SL-VCOM contact region can be etched to expose thecommon signal line SL as depicted in (C) of FIG. FIG. 8B. Afterstripping the photoresist, a transparent electrode layer (e.g., ITO) canbe deposited to be in direct contact with the common signal line SL viathe contact hole made through the upper planarization layer PLN-U andthe lower planarization layer PLN-L as depicted in (D) of FIG. FIG. 8B.

In this exemplary method, the formation of contact hole CT through thelower planarization layer PLN-L is performed after the annealingprocesses. In other words, any thermal expansion of the lowerplanarization layer PLN-L would have been already taken place when thecontact hole CT is being formed through the lower planarization layerPLN-L. Thus, stable connection between the common signal line SL and thecommon electrode block can be provided without using the bypass line BL.

[Coplanar Structure TFT]

In some embodiments, the TFTs on the lower planarization layer may havecoplanar structure, in which the gate, source and drain are provided onthe same side of the semiconductor layer SEM. FIG. 9A illustrates aplane view and a cross-sectional view of a coplanar TFT, which may beprovided in an exemplary embodiment of the present disclosure. FIG. 9Bis a cross-sectional view for illustrating the connection between thecommon signal line SL and the common electrode block according to anembodiment of the present disclosure.

Referring to FIGS. 9A and 9B, the common signal line SL is patternedfrom the first metal layer M1, and are covered under the lowerplanarization layer PLN-L. Similar to the display panel PNL withinverted staggered structure TFTs shown in FIG. 6B, passivation layersPAST and PAS2 may be provided on the lower surface and the upper surfaceof the lower planarization layer PLN-L. The lower contact hole CTL isprovided through the lower planarization layer PLN-L to open a part ofthe contact portion of the common signal line SL.

The semiconductor layer SEM (e.g., IGZO, poly-silicon) is provided onthe lower planarization layer PLN-L. A light shield LS may be providedin order to suppress light induced threshold voltage shift of the TFT.In this regard, the light shield LS may be patterned form the firstmetal layer M1 under the lower planarization layer PLN-L. As shown inFIG. 9A, a portion of the common signal line SL may be projected outtoward the active channel of the TFT to serve as the light shield LS. Itshould be noted that the routing portion of each of the common signalline SL at least partially overlaps with a data line, and the lightshield portions LS can project out from the routing portion of thecommons signal line SL can overlap with a part of the gate line GL. Assuch, each common signal line SL can include a plurality of light shieldportions LS projected out from its routing portion. In this way, boththe common signal lines SL and the light shields LS can be provided froma single metal layer, thereby reducing the time and cost formanufacturing the display panel PNL. In order to ensure that the lightshield portion LS of the common signal line protects the active channelof the TFT from the unwanted light, the light shield portion LSprojecting out from the common signal line SL may be sufficiently sizedand positioned so that at least some part of the light shield portion LSoverhangs outside the outer edge of the gate electrode provided on thesemiconductor layer. In some embodiments, at least some part of thelight shield portion LS overhangs outside the outer edge of thesemiconductor layer of the TFT.

If desired, a buffer layer BUF can be provided between the semiconductorlayer SEM and the lower planarization layer PLN-L. In this regard, thebuffer layer BUF may be provided in addition to the passivation layer(not shown) provided on the lower planarization layer PLN-L. Similar tothe passivation layers under and over the lower planarization layerPLN-L, the buffer layer BUF can be formed of a silicon nitride layer, asilicon oxide layer and a combination thereof. If the semiconductorlayer SEM to be provided on the buffer layer BUF is an oxide metalsemiconductor, such as IGZO, it is preferred that a silicon oxide layeris the outer most layer (i.e., the layer interfacing the semiconductorlayer) of the buffer layer BUF to shield the semiconductor layer SEMfrom the free/unbound hydrogen from any silicon nitride layer existingthereunder. For instance, a passivation layer formed of silicon nitridelayer may be provided on or below the lower planarization layer PLN-Land the buffer layer BUF formed of silicon oxide layer can be providedon the passivation layer.

A gate insulation layer GI is provided on the semiconductor layer. Then,the second metal layer M2 is patterned to form the gate line GL and thegate electrode of the TFTs on the gate insulation layer GI. After thepatterning of the second metal layer M2 for forming the gate lines GL,the gate electrode of the TFTs, the gate insulation layer GI may bepatterned by an etching process (e.g., dry etching). In this case, thegate insulation layer GI can patterned according to the pattern of thesecond metal layer M2 (e.g., according to the gate lines GL, gateelectrodes of the gate lines GL). In other words, the gate insulationlayer GI may remain under the gate lines GL and other metal structurepatterned form the second metal layer M2. Annealing process and/orplasma treatment is performed on the semiconductor layer. Also, thethird metal layer M3 is patterned to form the data lines DL and thesource/drain electrodes of the TFTs. An interlayer dielectric layer ILDis provided to insulate the gate electrode from the source/drainelectrodes. The upper planarization layer PLN-U is disposed on thecoplanar type TFTs described above, and a plurality of transparentelectrode blocks is provided on the upper planarization layer PLN-U.Each of the plurality of transparent electrode blocks may serve as acommon electrode VCOM during operation of the display panel PNL. Theplurality of transparent electrode blocks may also serve as a touchsensor during operation of the display panel PNL.

Each of the transparent electrode blocks is connected to at least one ofthe common signal line SL under the lower planarization layer. In someembodiments provided with the coplanar type TFTs, bypass lines BL may beused to connect the common signal lines BL under the lower planarizationlayer PLN-L and the common electrode blocks on the upper planarizationlayer PLN-U. The bypass lines BL may be patterned from the second metallayer M2. In such cases, the gate insulation layer GI may be remainedunder the bypass line BL as described above. Alternatively, in someother embodiments, the bypass lines BL may be patterned from the thirdmetal layer M3.

Further, in embodiments which the semiconductor layer SEM is formed ofan oxide metal layer such as IGZO, the oxide metal pattern formed fromthe lower contact hole CTL and the upper contact hole CTU may be turnedinto a conductive line to serve as the bypass line BL. That is, thebypass lines BL can be patterned from the oxide metal layer, which isturned into a conductive path by suitable doping process, including butnot limited to, plasma enhanced chemical vapor deposition (PECVD),hydrogen plasma treatment, argon plasma treatment and the like.

It should be appreciated that such heavily doped oxide metal paths canbe provided in various other parts of the display panel PNL. Forexample, conductive lines in the non-display area of the display panelPNL may be formed from doped oxide metal patterns. Also, in someembodiments, the gate driver GD of the display panel PNL may be providedas a gate-in-panel (GIP) type, which is implemented with a plurality ofTFTs directly formed at the non-display area of the display panel PNL.In the embodiments provided with the GIP type gate driver GD, some nodesin the circuitry of the GIP may be formed with the heavily doped oxidemetal patterns.

It should be noted that the TFTs implementing the GIP circuit is notjust limited to the oxide TFTs, and the GIP circuit may be implementedwith LIPS TFTs. In other words, both oxide TFTs and LIPS TFTs may beprovided on the TFT substrate of the display panel PNL. By way ofexamples, the pixel circuits in the display area of the display panelPNL may be implemented with oxide TFTs and the driving circuits (e.g.,buffer, shift register, multiplexer, GIP, etc.) in the non-display areamay be implemented with LIPS TFTs. The pixel circuit implemented withthe oxide TFTs would provide higher voltage holding ratio than the LIPSTFT, which would be beneficial when temporarily reducing the frame rate(i.e., frames per second) of the display to conserve power while thedisplay is being used in applications which do not require high framerate. The driving circuits implemented with the LIPS TFTs would bebeneficial high frequency driving of various components, such as thetouch driver, especially when IFP touch scanning scheme is used.

Also, a combination of both oxide TFTs and the LIPS TFTs may be used toimplement the pixel circuits and/or the driving circuits. For instance,oxide TFTs may be used to fabricate the IFP compensation circuit (whichwill be described in detail below), while LIPS TFTs are used toimplement the rest of GIP circuitry. If a storage capacitor is used inthe pixel circuit and/or the driving circuit, the transistors connectedto the terminals of such storage capacitors may be oxide TFTs eventhough LIPS TFTs are used in other parts of the circuitry. As will bedescribed in greater detail below, an IFP compensation circuit includesa storage capacitor and the transistors connected at the terminals ofthe storage capacitor may be oxide TFT while LIPS TFTs are used forother parts of the GIP circuit.

In the non-display area where the common signal lines are not routed,the oxide TFTs and the LIPS TFTs can be provided in a different layerfrom each other. For instance, the LIPS TFTs may be provided under thelower planarization layer PLN-L and the oxide TFTs may be provided onthe lower planarization layer PLN-L, and vice versa. Accordingly, inembodiments provided with both oxide TFTs and LIPS TFTs, the pixelcircuits and/or the driving circuits of the display panel PNL mayinclude a node and/or electrode formed with doped oxide metal pattern(i.e., conductive line formed from the oxide metal semiconductor layer).In the embodiments where the combination of oxide TFTs and LIPS TFTs areprovided on the TFT substrate (TFT backplane), TFTs can be provided inany of the coplanar structure and the inverted staggered structure. Insome cases, either the oxide TFTs or the LIPS TFTs may be implemented inthe coplanar structure, and the other TFTs may be provided in theinverted staggered structure.

Also, in some embodiments provided with the coplanar type TFTs, thecommon signal lines SL may be in a direct contact with the commonelectrode blocks via a contact hole through the upper planarizationlayer PLN-U and the lower planarization layer PLN-L.

[Non-Display Area: SOG Open Area]

In some embodiments, a drive integrated circuit (D-IC) and/or FPCBhaving a driver can be connected to a connection interface provided inthe non-display area of the display panel PNL. FIG. 10A and FIG. 10Beach illustrates a schematic illustration of an exemplary configurationof a connection interface for a driver in the non-display area of thedisplay panel PNL.

Referring to FIG. 10A, some part of the non-display area is providedwith the lower planarization layer PLN-L and some other part of thenon-display area is free of the lower planarization layer PLN-L. Forsimpler explanation, the part of the non-display area is provided withthe lower planarization layer PLN-L may be referred to as the “SOGarea,” and the part of the non-display area without the lowerplanarization layer PLN-L may be referred to as the “SOG Open Area.”

If the connection interface is provided on the lower planarization layerPLN-L, the lower planarization layer PLN-L may be damaged when attachingthe D-IC or detaching the D-IC for repair. As such, it is preferred thatthe connection interface for the D-IC is positioned in the SOG open areaof the non-display area.

To provide the connection interface in the SOG open area, a plurality ofmetal line traces is routed from the SOG area to the SOG open area. Asshown, the metal line traces routed to the SOG open area may be themetal line traces patterned from the first metal layer M1. Each of themetal line traces exposed in the SOG open area may include a portionthat is configured as a bump (e.g., pad), which is a part of theconnection interface. In some embodiments, the bumps may be formed ofmultiple metal layers. For example, the second metal layer M2 may bedisposed on the bump portions of the metal line traces patterned fromthe first metal layer M1. Of course, additional metal layers can beprovided on top of the bump portions of the underlying metal layer. Insuitable embodiments, the metal line traces routed from the SOG area tothe SOG open area may be the common signal line SL and a touch drive ICor a FPCB provided with a touch driver is attached to the bumps providedin the SOG open area.

Referring to FIG. 10B, in some embodiments, the metal line traces routedfrom the SOG area to the SOG open area may be patterned from the secondmetal layer M2. In this case, the common signal lines SL can be routedto the SOG area of the non-display area, and metal line traces patternedfrom the second metal layer M2 can be routed from the SOG area to theSOG open area. The common signal lines SL in the SOG area can come incontact with the metal line traces patterned from the second metal layerM2 via the lower contact holes CTL provided in the SOG area. The metalline traces of the second metal layer M2 in the SOG open area mayinclude portions configured as the bumps for connecting touch drive ICand/or FPCB with a touch driver. Although this configuration requirescontact holes (i.e., jumping holes) to be formed in the non-displayarea, the common signal lines SL will not be damaged during patterningof the second metal layer M2.

In some suitable embodiments, the data link lines that fan out from thedata driver DD may be routed from the SOG open area to the SOG area asdepicted in FIG. 10B. Here, the data link lines may be patterned fromthe second metal layer M2 or the third metal layer M3, and they cansimply be routed on the lower planarization layer PLN-L in the SOG area.The metal line traces, which are connected to the common signal lines SLthrough the lower contact hole CTL in the non-display area, may be thetouch link line connected to a touch drive IC. In this setting, the datalink lines connected to the data driver DD may fan out across the commonsignal lines SL placed under the lower planarization layer PLN-L,allowing for a reduced bezel design of the device equipped with thedisplay panel PNL.

[Gate-in-Panel: GIP]

The gate driver GD of the display panel PNL may be provided as agate-in-panel (GIP) type, which is implemented with a plurality of TFTsdirectly formed at the non-display area of the display panel PNL. Insome embodiments, the TFTs of the GIP circuit may be formed on the lowerplanarization layer, similar to the array of TFTs in the display area ofthe display panel PNL. In such embodiments, the conductive lines forsupplying external signals to the GIP circuit can be provided underneaththe lower planarization layer PLN-L. For instance, a plurality ofexternal signal lines can also be patterned in the non-display area ofthe display panel PNL when patterning the first metal layer M1 on thesubstrate to provide the common signal lines SL across the display areaof the display panel.

FIG. 11A illustrates an exemplary configuration of a stage in anexemplary GIP circuit, which may be provided in the display panel PNL.As shown in FIG. 11A, the external signal lines provided to the GIPcircuit may include various clock signal lines, power signal lines(e.g., VSS, VDD), reset signal lines and more. Such external signallines are routed in the non-display area of the display panel PNL. Morespecifically, the external signal lines may be formed with the firstmetal layer M1 and provided under the lower planarization layer PLN-L.In this way, the external signal lines may be routed under the pluralityof TFTs in the non-display area implementing the shift register of theGIP circuit. The external signal lines can be connected to therespective nodes of the GIP circuit via contact holes through the lowerplanarization layer PLN-L. In some embodiments, signal line fortransmitting the common voltage signal may be routed in the non-displayarea under the GIP circuit. Routing at least some of the external signallines directly under the GIP circuit allows to reduce the bezel sizeeven further.

[Exemplary Capacitor Configuration]

In some embodiments, capacitors included in the GIP circuits may beimplemented with a metal layer under the lower planarization layerPLN-L. For instance, each stage of the shift register in the GIP circuitincludes a pull-up TFT T6, which is configured to output a scan signalon the output terminal Vgout(N). The pull-up TFT T6 has its gateconnected to the Q-node, the first terminal connected to the voltagesource CLK and the second terminal connected to the output terminalVgout(N) of the respective stage. Accordingly, the pull-up TFT T6controlled by the voltage on the Q-node.

A capacitor CAP may be connected between the gate and the secondterminal of the pull-up TFT T6. During operation of the shift register,the voltage of the Q-node is increased to a higher voltage bybootstrapping of the capacitor CAP connected between the Q-node and theoutput terminal, thereby completely turning on the pull-up TFT T6.

The capacitor CAP may be configured as a parasitic capacitor which isformed in an overlapping area between the gate and source of the pull-upTFT T6, which are formed of the second metal layer M2 and the thirdmetal layer M3, respectively. The dimension of the capacitor CAP in theGIP circuit may be considerably large. Accordingly, the dimension of thecapacitor CAP may be reduced to reduce the size of the GIP circuit inthe non-display area of the display panel PNL.

To this end, the first metal layer M1 can be patterned to provide anadditional metal layer under the lower planarization layer PLN-L toimplement the capacitor CAP. As shown in FIG. 11B, the capacitor CAP canbe formed in an overlapping area between the first capacitor plate CP1patterned from the first metal layer M1, the second capacitor plate CP2patterned from the second metal layer M2 and the third capacitor plateCP3 patterned from the third metal layer M3, of which the firstcapacitor plate CP1 and the third capacitor plate CP3 are electricallyconnected to each other. The third capacitor plate CP3 can be connectedto the first capacitor plate CP1 via a contact hole CTL provided throughthe lower planarization layer PLN-L. As shown, a contact bridge formedof the second metal layer M2 may be provided to electrically connect thefirst capacitor plate CP1 and the third capacitor plate CP3. Of course,the contact bridge formed of the second metal layer M2 is disconnectedfrom the second capacitor plate CP2. By stacking up three metal plates,more compact sized capacitor can be provided without having to sacrificethe total charge storage capability. This, in turn, facilitates morecompact sized GIP circuits.

In some embodiments, the thickness of the lower planarization layerPLN-L interposed between the first metal plate CP1 and the second metalplate CP2 can be reduced in order to further increase the amount ofcapacitance that can be stored in the capacitor CAP. To this end, ahalf-tone mask may be used when forming the lower contact hole CTLthrough the lower planarization layer PLN-L. More specifically, whenforming the lower contact hole CTL, a photoresist can be placed over thelower planarization layer PLN-L, and the photoresist can be developed byusing the half-tone mask. The photoresist over the lower planarizationlayer PLN-L at the first metal plate CP1 can have a reduced thickness.Accordingly, the thickness of the lower planarization layer PLN-L at thecapacitor CAP can also be reduced when dry-etching process for creatingthe lower contact hole CT is performed. Similar process can be used informing various other capacitors described in the present disclosure.

It should be noted that the shift register of the GIP circuit mayinclude capacitors other than the one described above. Similar to thecapacitor CAP connected between the Q-node and the output terminalVgout(N) of the stage, other capacitors may also be formed of a stack ofa first capacitor plate CP1, a second capacitor plate CP2 and a thirdcapacitor plate CP3.

[Intra-Frame Pause Compensation Circuit]

As discussed above, in some embodiments, a display panel PNL can beconfigured to operate in the intra-frame-pause (IFP) touch scan schemeto provide enhanced touch scan resolution.

In the GIP circuit, each stage of the shift register outputs a scansignal on the gate line GL, which is connected with the output terminalof the stage. Also, the scan signal from one stage is supplied toanother stage of the shift register as a start signal so that the stagereceiving the start signal operates to output the scan signal on thegate line GL connected thereto. Thus, the scan signal is supplied on allof the gate lines GL in a sequential order per each frame.

However, when the IFP scheme is used, the sequential output of the scansignal on the gate lines GL is temporarily paused while the touch scanoperation is being performed. In other words, a stage of the shiftregister is prevented from outputting the scan signal until intra frametouch scan operation is completed. To resume and output the scan signalfrom last gate line GL which was provided with the scan signal, theQ-node need to be charged at the high-state. One way of resuming theoperation of the shift register is by keeping the Q-node at the highstate while IFP touch scan operation is be performed. That is, theQ-node of the stage which received the start signal from a previousstage may simply remain at high state. In this case, however, thepull-up TFT connected to the high state Q-node for a prolonged periodmay deteriorate faster than other TFTs of the GIP circuits.

Accordingly, in some embodiments, the display panel PNL may include aGIP circuit having a compensation circuit adapted for the IFP drivingscheme. The compensation circuit allows the Q-node to be dischargedwhile the IFP touch scan operation is being performed by storing thevoltage of the Q-node in a storage capacitor during the IFP touch scanoperation and recharging the Q-node with the stored voltage after theIFP touch scan operation.

FIG. 12A is a schematic circuit diagram showing an exemplaryconfiguration of the compensation circuit which can be provided in oneor more stages of a GIP circuit. It should be noted that thecompensation circuit depicted in FIG. 12A is only a part of circuitry ina stage, and thus the circuitry of a stage would include various othertransistors including but not limited to the pull-up transistor. Forinstance, the compensation circuit in FIG. 12A can be added to thecircuitry of a stage depicted in FIG. 11A.

Referring to FIG. 12A, the compensation circuit includes a firsttransistor TIFP1, a second transistor TIFP2, the third transistor TIFP3and the fourth transistor TIFP4. The first transistor TIFP1 is connectedbetween the Q-node and the low voltage line VSS, and the gate of thefirst transistor TIFP1 is connected to a node, which is supplied with anIFP signal. The second transistor TIFP2 is connected between the highvoltage line VDD and the gate of a fourth transistor TIFP4, and the gateof the second transistor TIFP2 is also connected to the high voltageline VDD. The third transistor TIFP3 is connected between the gate ofthe fourth transistor TIFP4 and the low voltage line VSS, and the gateof the third transistor is connected to the node, which is supplied withthe IFP signal. The second transistor TIFP2 and the third transistorTIFP3 are serially connected between the high voltage line VDD and thelow voltage line VSS, acting as an inverter in the compensation circuitthat controls the fourth transistor TIFP4.

The fourth transistor TIFP4 has a first terminal TM1 connected to astorage capacitor CIFP, a second terminal TM2 connected to the Q-nodeand the gate connected to the node between the second transistor TIFP2and the third transistor TIFP3, which are serially connected between thehigh voltage line VDD and the low voltage line VSS. The compensationcircuit includes a storage capacitor CIFP, which is connected betweenthe first terminal TM1 of the fourth transistor TIFP4 and the lowvoltage line VSS.

In operation, a Q-node of a stage is charged in response to a startsignal from a previous stage (or via an external start signal line). Asmentioned, the stage is provided with a compensation circuit. Thus, anIFP signal, which indicates the start and the end of IFP touch scanoperation, is supplied to the stage. In response to the low IFP signal,the voltage of the Q-node is stored in the storage capacitor CIFP. Asshown in FIG. 12B, the Q-node is discharged in response to the highlevel IFP signal. When the IFP signal is switched back to the low level,the Q-node of the stage is charged to the voltage stored in the storagecapacitor CIFP, and outputs the scan signal. In this way, the Q-node canbe discharged during the period for carrying out the IFP touch scanoperation, thereby minimizing the deterioration of the pull-uptransistor.

It should be noted that, in some embodiments, the start timing of theIFP touch scan operation within a frame may be fixed. In other words,the display panel PNL may be configured to begin the IFP touch scanoperation after the scan signal is supplied on each of a pre-specifiednumber of gate lines GL within a frame. That is, one or morepre-specified stages of the shift register may be configured to bepaused in sync with the IFP touch scan operation. In such embodiments,the compensation circuit may be added to the circuitry of thosepre-specified stages configured to be paused during the IFP touch scanoperation.

In some other embodiments, the start timing of the IFP touch scanoperation within a frame may vary. For instance, the timing of the IFPsignal hitting the high stage may vary between any two display periodswithin a single frame. Since the timing of the IFP signal varies, thestage of be paused for IFP touch scan operation also varies. As such,the stage to be paused during the IFP touch scan operation can be one ofa set of pre-specified stages (i.e., a plurality of stages of apre-specified range). The display panel PNL can be configured such thatthe timing of the high IFP signal varies for each frame. In such cases,the high level IFP signal can be supplied to a different stage of theset of pre-specified stages to receive the high level IFP signal. Insuch embodiments, all of the stages in the set of pre-specified stages,which may receive the high level IFP signal, can be provided with thecompensation circuit.

Similar to the bootstrapping capacitor (e.g., CAP) discussed inreference to FIG. 11A, the storage capacitor CIFP of the compensationcircuit may be implemented with the first metal plate CP1 patterned fromthe first metal layer M1, the second metal plate CP2 patterned from thesecond metal layer M2 and the third metal plate CP3 patterned from thethird metal layer M3. As mentioned above, the second metal plate CP2 isinterposed between the first metal plate CP1 and the third metal plateCP3 connected to the first metal place CP1. In this setting, increasedamount of charge can be stored in the storage capacitor CIFP so that,upon the end of the IFP touch scan operation, the Q-node can be properlyreloaded with the initial high voltage of the Q-node before the IFPtouch scan operation started as shown in FIG. 12B.

[Dummy Line Configuration]

In order to implement a touch sensor in the display panel PNL by usingthe segmented pieces of transparent electrodes (e.g., segmented piecesof a common electrode), each individual pieces needs to be connected toat least one common signal line SL. Thus, the minimum number of commonsignal lines SL required in the display panel would be equal to thenumber of common electrode blocks. However, it should be appreciatedthat a display panel PNL may be provided with much greater number ofcommon signal lines SL than the bare minimum required in the displaypanel PNL. With extra common signal lines SL provided in the displaypanel PNL, multiple common signal lines SL can be connected to a singlecommon electrode block to provide a low resistance connection betweenthe common electrode block and the driver.

If desired, a common signal line SL can be provided under each and everydata lines DL, and they may be connected to the common electrode blocksto implement either a self-capacitance touch sensor system, amutual-capacitance touch sensor system or to provide various otherfunctionalities (e.g., touch pressure sensor system, localized tactilefeedback system, etc.) in the display panel PNL.

With a common signal line SL being placed under every data lines DL,uniformity in the capacitance between the data line DL and the commonsignal line SL throughout the display panel PNL may be achieved.However, part of the common signal line SL routed under the commonelectrode blocks that are not connected to that particular common signalline SL increases undesired capacitance at those common electrodeblocks. As such, dummy lines DML, which are not directly connected tothe touch driver TD, can be provided in place of unnecessary portions ofthe common signal lines SL. That is, in order for the data lines DL tohave uniform data line capacitance, dummy lines DML may be provided inthe display panel PNL, so that every data lines DL in the display panelare overlapped with either the common signal line SL or the dummy lineDML as depicted in FIG. 6A. Since the dummy lines DML do not need to beconnected to the common electrode blocks, the number of total bypasslines BL needed in the display panel PNL can be greatly reduced, whichwould improve the aperture ratio of the pixels in the display panel PNL.

It should be appreciated that both a common signal line SL and a dummyline DML may be laid under a single data line DL. To put it in otherway, a conductive line patterned from the first metal layer M1 routedalong under a single data lines DL may be separated into multipledisconnected portions, in which a portion serves as the common signalline SL connected to the touch driver TD and other portion serves as thedummy line DML. For example, a common signal line SL may be extendedunder a data line DL and connected to a common electrode block. Thecommon signal line SL would end at a point where it is connected to thecommon electrode block. From thereon, a conductive line disconnectedfrom the common signal line SL can be extended under the data line DL asa dummy line DML.

The dummy lines DML in floating state may cause electrostatic duringmanufacturing of the display panel PNL. As such, in some embodiments,the dummy lines DML may be connected to a voltage source, such as acommon voltage source, a DC voltage source or a ground voltage source. Acommon signal line SL divided into multiple portions under the same dataline DL may include isolated dummy line DML portions, which cannot beextended to a voltage source located outside the display area.Accordingly, in some embodiments, some dummy lines DML may be connectedto the common electrode blocks via the bypass lines BL. In such cases, adummy line DML should not interconnect multiple common electrode blocksthat are individually communicating with the touch driver TD via aseparate one or a set of common signal lines SL. The dummy lines DML canbe connected to the common electrode blocks so long as their connectionto the common electrode blocks do not alter the electrical connectionmap of the common electrode blocks for implementing a certain featurethat is defined by the common signal lines SL.

FIG. 13 illustrates exemplary configuration of a display panel PNLprovided with a plurality of isolated dummy lines DML, in which thedummy lines DML are selectively connected to a corresponding ones ofcommon electrode blocks. The connection between the dummy lines DML tothe common electrode block can be made through the bypass line BL in thesame way as the common signal lines SL. As shown, the dummy lines DMLare not in a floating state as being connected to the common electrodeblocks thereon. However, the isolated dummy lines DML do notinterconnect different common electrode blocks. Even though the dummylines DML are not directly connected to the touch driver TD on theirown, the dummy lines DML can serve as a current path relaying a signalwithin a single common electrode block.

In the example shown in FIG. 13, each of the dummy lines DML wasconnected to a common electrode block via multiple bypass lines BLlocated at different locations of the common electrode block. It shouldbe appreciated that a common signal lines SL may also be connected tomultiple bypass lines BL connected to different locations of the samecorresponding common electrode block.

Referring back to the example shown in FIGS. 6A-6C, the contact portionof the common signal line SL is depicted as being extended into thepixel region that is immediately adjacent to the routing portion of thatcommon signal line SL. However, the configuration of the contact portionis not limited as such, and the contact portion may be extended furtherinto other pixel regions. If dummy lines DML are disposed in the displaypanel PNL, the dummy lines DML under each data line DL may be providedin divided pieces so as to provide a passage for the contact portion ofthe common signal line SL to extend across the dummy lines DML.

In embodiments where dummy lines DML under some of the data lines DL areconnected to the common electrode blocks placed above as depicted inFIG. 13, the dummy lines DML would also include a routing portionextending parallel to the data lines DL and a contact portion projectingout from the routing portion to be connected to a bypass line BL. Thecontact portions of the dummy lines DML may also be transverselyextended across multiple pixel regions. In this case, other dummy linesDML under the data lines DL may be provided in divided pieces so as toprovide a passage for the contact portion of the dummy line DML to passacross. It should be noted that the contact portion of a dummy line DMLcan be in contact with other dummy lines DML along the way as long asthose dummy lines DML are not connected to a different common electrodeblock.

[Resistance-Capacitance Compensation]

Some common electrode blocks are located further away from a driver(e.g., touch driver TD) than others, and require a longer signal path tocommunicate with the touch driver TD. In embodiments where the commonelectrode blocks are configured to communicate with the touch driver TD,the differences in the length of the common signal lines SL forming thesignal path translate into resistance-capacitance delay (RC delay)differences between the common electrode blocks, which would complicatethe recognition of touch inputs. To compensate the resistancedifferences between the signal paths for the common electrode blocks,some signal paths can be implemented with a greater number of commonsignal lines SL than the others.

Accordingly, some of the common electrode blocks can be configured tocommunicate with the touch driver TD via a signal path formed of a setof common signal lines SL. The common signal lines of the set may beconnected to each other in parallel. In other words, aparallel-connection signal path implemented with at least two commonsignal lines SL can be provided for at least some of the commonelectrode blocks.

Connecting the common signal lines SL of the set in parallel to form aparallel-connection signal path can be done in various ways. In someembodiments, the parallel connection of the common signal lines SL of aset can be achieved by simply patterning an interconnection line fromthe first metal layer M1 during patterning the common signal lines SL inthe first place. In other words, a metal line may be patterned from thefirst metal layer M1 to extend across selective location of the commonsignal lines SL of the set and interconnect them to form aparallel-connection signal path. In this case, the interconnection linemay be arranged to at least partially overlap with a gate line GL tominimize the effect which the interconnection line might have on theaperture ratio of the pixel regions. The parallel-connection signal pathimplemented with the set of parallel-connected common signal lines SLcan be connected to the common electrode block using any one of theconfigurations described in this disclosure.

In some other embodiments, a bypass line BL commonly shared among thecommon signal lines SL of the set can serve as a means for creating theparallel-connection for the set of common signal lines SL. In yetanother embodiment, each common signal line SL in the set may discretelyconnected to the same common electrode block, in which case, the commonelectrode block itself will create the parallel connection between thecommon signal lines SL of the set.

The greater the number of common signal lines SL in the parallelconnection signal path, the lower the resistance of the signal pathbecomes. Accordingly, some parallel-connection signal path may include agreater number of common signal lines than other signal paths. Forinstance, a set of common signal lines SL that forms aparallel-connection path for a common electrode block positioned furtheraway from the touch driver TD can be implemented with additional numberof common signal lines SL than a set of common signal lines SL thatforms a parallel-connection path for the common electrode blockspositioned closer to the touch driver TD. In other words, a firstparallel-connection signal path for a common electrode block can beimplemented with N number of common signal lines SL, and a secondparallel-connection signal path for another common electrode block canbe implemented with M number of common signal lines. When the commonelectrode block that is connected with the first parallel-connectionsignal path is placed further away from the touch driver TD than thecommon electrode block connected with the second parallel-connectionsignal path, N may be greater than M.

FIG. 14A illustrates an exemplary configuration of common signal linesSL for normalizing the resistance differences among the common electrodeblocks of the display panel PNL, according to an embodiment of thepresent disclosure. In the display panel PNL, the common electrodeblocks may be arranged in “X” number of rows and “Y” number of columns,for instance 48 rows by 36 columns. Also, pixels may be arranged in “I”number of rows by “J” number of columns, for instance 45 rows by 45columns. Each pixel may include three sub-pixels (RGB). However, itshould be appreciated that the arrangements of the common electrodeblocks and the pixels described above are merely an example. The numberof common electrode blocks, the number of pixels, the number ofsub-pixels as well as their colors may vary in other embodiments of thepresent disclosure.

As mentioned, at least for some common electrode blocks, the signal pathfrom the touch driver TD to the respective common electrode block can beimplemented with multiple common signal lines SL, which are connected inparallel. In the example shown in FIG. 14A, each of the signal paths forthe common electrode blocks of the column numbered 1 through 37 areimplemented with at least two parallel-connected common signal lines SL.In some cases, common electrode blocks positioned relatively close tothe touch driver TD may not be provided with such parallel connectionsignal paths. As such, the signal paths for the common electrode blocksnumbered 38 through 48 of the same column are implemented with a signalpath formed of a single common signal line SL.

As mentioned above, some parallel connection signal paths canimplemented with an increased number of parallel-connected common signallines SL. However, it should be noted that the total number of commonsignal lines SL that can be placed under each common electrode block maybe limited. Therefore, it may not be feasible to increment the number ofcommon signal lines SL in each and every parallel-connection signalpaths for the common electrode blocks of the column. Accordingly, insome embodiments, some common electrode blocks may be provided with asignal path that is implemented with equal number of common signal linesSL as the signal path for other common electrode blocks even though oneis positioned closer to the touch driver TD than the other. In suchembodiments, the common electrodes blocks arranged in each column may bedivided into a plurality of groups of common electrode blocks, of whichthe groups are defined based on the distance between the touch driver TDto the common electrode blocks. Here, the signal path for every commonelectrode block of in same group may be implemented with the equalnumber of common signal line(s).

In the example depicted in FIG. 14A, the common electrode blocks of asingle column includes five groups (N1, N2, N3, N4 and N5). The commonelectrode blocks of the first group N1 are positioned closer to thecommon electrode blocks of the other groups. The common electrode blocksof the second group N2 are positioned further away from the touch driverTD than the common electrode blocks of the first group N1, but notfurther than the common electrode blocks of the third group N3. Thecommon electrode blocks of the fourth group N4 are positioned furtheraway from the touch driver TD than the common electrode blocks of thethird group N3, but not further than the common electrode blocks of thefifth group N5.

In this setting, the differences in resistance of the signal paths fromthe touch driver TD to the common electrode blocks are compensated byadjusting the number of common signal line SL creating those signalpaths. As such, the first group N1, the second group N2, the third groupN3, the fourth group N4 and the fifth group N5 of the column includesthe common electrode blocks from #38 through #48, from #27 through #37,from #18 through #26, from #8 through #17 and from #1 through #7,respectively. Since the first group N1 is the closest to the touchdriver TD, the signal path for each of the common electrode blocks ofthe first group N1 is configured with a signal path implemented with asingle common signal line SL. As for the second group N2, the parallelconnection signal path for each of the common electrode blocks isconfigured with two parallel-connected common signal lines SL. As forthe third group N3, the parallel connection signal path for each of thecommon electrode blocks is configured with three parallel-connectedcommon signal lines SL. Further, as for the fourth group N4, theparallel connection signal path for each of the common electrode blocksis configured with four parallel-connected common signal lines SL.Lastly, as for each of the common electrode blocks of the fifth groupN5, the parallel connection signal path is configured with five commonsignal lines SL that are connected in parallel.

In the example of FIG. 14A, the resistance differences among the signalpaths are compensated between the groups of common electrode blocks inthe column. However, the resistance difference still exists among thecommon electrode blocks within the same group. When the number commonelectrode blocks included in each group increases, the resistancedifferences for the signal path among the common electrode blocks of thesame group may not be negligible. As such, in some embodiments, thesignal path between the touch driver TD and the common electrode blockmay include a tail portion for secondary adjustment of the resistance ofthe signal path. The tail portion of the signal path can be adjusted tofurther normalize the resistance of the signal paths for the commonelectrode blocks of the same group.

FIG. 14B is an exemplary configuration of tail portions for secondaryadjustment of resistance difference between the signal paths for thecommon electrode blocks. The signal path #1 may be the one that isconnected to the common electrode block #1 and the signal path #7 may bethe one that is connected to the common electrode block #7. As shown,the signal paths #1 and #7 includes a main portion M and a tail portionT. The tail portion T may be another parallel connection signal pathformed at the end of the parallel connection signal path of the mainportion M, only that the parallel connection signal path of the tailportion T is implemented with a lesser number of common signal lines SLthan the parallel connection signal path of the main portion M.

In the example depicted in FIG. 14B, the parallel connection signal pathof the tail portion T is formed of n−1 number of common signal lines SL,of which “n” denotes the total number of common signal lines SL used informing the parallel connection signal path of the main portion M.However, it should be appreciated that the number of common signal linesSL for forming the parallel connection of the tail portion T is notlimited to n−1. As such, in some embodiments, the tail portion of asignal path can be implemented with n−2, n−3 and so on. In some cases, aparallel connection signal path may be provided with a tail portion Tthat is formed of a single common signal line SL. For instance, thesignal paths #27 and #37, which may be connected to the common electrodeblocks #27 and #37, includes a parallel connection main portion M formedof two parallel-connected common signal lines SL and a tail portion Tformed of a single common signal line SL.

In the example depicted in FIG. 14B, all of the signal paths for thecommon electrode blocks of the same group include a tail portion T. Thetail portions T of those signal paths are implemented with the samenumber of common signal lines SL. For example, the tail portions T ofthe signal paths #1 through #7 are implemented with n−1 (i.e., 4 in thiscase) number of common signal lines SL. For more precise adjustment, thetail portions T of some of the signal paths can be configureddifferently from the tail portions T of other signal paths. Usingdifferent tail portion T may be particularly useful for the signal pathsof the common electrode blocks of the same group, which each signal pathhas the main portion M implemented with the same number of common signallines SL as one another. For the signal paths of the common electrodeblocks of the same group, the tail portion T may not be much of a use incompensating the resistance differences if all of those signal paths areprovided with the tail portion T configured in the exactly the same wayas each other.

Accordingly, in some embodiments, the tail portion T of signal paths maybe implemented with a different number of common signal lines SL eventhough those signal paths include the main portions M implemented withthe same number of common signal lines SL as one another. FIG. 14Cillustrates an exemplary configuration of signal paths having the samemain portions M but provided with different tail portions T. In theexample depicted in FIG. 14C, each of the signal paths #1 through #7 mayhave a main portion M implemented with n number of common signal linesSL (5 in the example of FIG. 14C). However, the tail portion T of thesignal path #1 may be implemented with n−1 (e.g., 4) number of commonsignal lines SL and the tail portion T of the signal path #7 may beimplemented with n−2 (e.g., 3) number of common signal lines SL.

FIG. 14D illustrates an exemplary configuration of the signal paths forthe common electrode blocks of the same group. In some embodiments,among the signal paths implemented with the same number of common signallines SL, only some signal paths may be provided with the tail portionT. For instance, the signal path #1 may not be provided with a tailportion T, even though the main portion M for both the signal path #1and the signal path #7 are implemented with the same number of commonsignal lines SL.

Moreover, in some embodiments, the length of the tail portion T can beadjusted to compensate for the resistance differences of the signalpaths. For instance, the tail portion T of the signal path #1 and thetail portion T of the signal path #7 may be provided in a differentlength as shown in FIG. 14E.

It may be difficult to adjust the resistance of the signal path with atail portion implemented with a single common signal line SL. Forexample, the length of a single common signal line SL for implementingthe tail portion may not fit under the common electrode block which thetail portion needs to be connected. As such, in some embodiments, somesignal paths may be provided with a tail portion T implemented with atleast two common signal lines SL, which are connected in serialconfiguration.

FIG. 14F illustrates an exemplary configuration of common signal linesSL for implementing a signal path with a serial-connection tail portion.Referring to FIG. 14F, a signal path includes a parallel connection mainportion M and a serial-connection tail portion T. The serial-connectiontail portion T is implemented with at least two parts (denoted 1 and 2),which are conductive lines patterned from the first metal layer M1 andplaced under different data lines DL. An interconnection line can beused to serially connect the two parts, thereby implementing the serialconnection tail portion T. In this regard, the collective length of theserial connection tail portion can be adjusted by adjusting the lengthof either parts (denoted 1 and 2). It should be noted that suchserial-connection tail portion may also be provided for the signal pathshaving the parallel main portion implemented with more than two commonsignal lines SL.

In the previous examples, each of the signal paths for the commonelectrode blocks of the first group N1, which is the group that isclosest to the touch driver TD, was implemented with a single commonsignal line SL. With a single common signal line SL, resistance of thesignal path is very heavily dependent on the length of the common signalline SL. Thus, it can be difficult to normalize the resistance of thesignal paths when the entire signal path is implemented with a singlecommon signal line SL. Accordingly, in some embodiments, all signalpaths for the common electrode blocks of the display panel PNL may beimplemented with at least two common signal lines SL connected inparallel. In such embodiments, each and every signal paths between acommon electrode block to the touch driver TD may include at least oneparallel connection portion. Some signal paths may include the tailportion and some may not. For those signal paths including the tailportion T, the tail portion T can be implemented with a single commonsignal line SL, multiple common signal lines SL connected in serialconfiguration or multiple common signal lines SL connected in parallel.

As discussed above, the dummy lines DML that are disconnected from thecommon signal lines SL can be arranged under the data lines DL. Asdepicted in FIGS. 14B-14E, the dummy lines DML under the data lines DLmay be disconnected from the parallel connection signal paths describedabove. Also, some of the common signal lines SL implementing theparallel connection signal path may be continuously extended across thedisplay area.

Signal paths for common electrode blocks of other columns of commonelectrode blocks may also be configured in the similar way as describedabove. However, it should be noted that the configuration of signalpaths for the column of common electrode blocks needs not be the samefor every column of common electrode blocks. Some columns of commonelectrode blocks may have a different signal path configuration from aconfiguration of signal paths in other column of common electrodes.

[Contact Hole Position]

As mentioned, the common signal lines SL are routed across the displayarea of the display panel PNL along the data lines DL. This allows therouting portion of each common signal line SL to be at least partiallyoverlap with the data line DL provided thereon. However, the contactportion transversely projected out from the routing portion of thecommon signal line SL may not be covered under the data line DL.

Also, the bypass lines BL cannot be positioned to overlap with the gatelines GL because the bypass lines BL are formed of the second metallayer M2, which is the same non-transparent metal layer of the gatelines GL and the gate electrode of the TFTs. In LCD devices, the bypasslines BL would block the light from the light source (e.g., backlight)to pass through, effectively reducing the aperture of the pixels. Evenfor self-light emitting display such as the OLED display, the bypasslines BL can reflect external light and make it difficult to see theimages on the screen. Thus, the contact portion of the common signalline SL as well as the bypass lines BL is concealed under a maskinglayer BM in a similar way as the gate lines GL and data lines DL areconcealed under the masking layer BM. The same applies to the contactportion of the dummy lines DML and the bypass lines BL connecting thedummy lines DML to the corresponding ones of the common electrodeblocks.

Since the masking layer BM defines the aperture ratio of the pixels,covering the bypass lines BL results in reduction in the aperture ratioof the pixels where the bypass lines BL are arranged therein. Because atleast one bypass line BL is needed to connect a common signal line SL tothe common electrode block, each pixel group sharing a common electrodeblock may include pixels with different aperture ratios. For instance,the maximum aperture ratio of the pixel region with the lower contacthole CTL may differ from the maximum aperture ratio of the pixel regionwith the upper contact hole CTU. Also, the maximum aperture ratio of thepixel regions where the interim section of the bypass line BL is laidacross may be different from the maximum aperture ratio of the pixelregions accommodating the lower or the upper contact holes. Further,some pixels may not be accommodating any of the contact holes or thebypass line BL, and allowed with a greater maximum aperture ratio thanthe maximum aperture ratio of other pixels. Herein, the pixels with areduced maximum aperture ratio due to the contact holes or the bypasslines BL may be referred to as the “bypass pixels.” The pixels in whichthe maximum aperture ratio is not reduced by the contact holes or thebypass lines BL may be referred to as the “normal pixels.”

Referring back to FIG. 6A, the lower contact hole CTL for connecting thecommon signal line SL to the bypass line BL is provided in one of thepixel region, and the upper contact hole CTU for connecting the bypassline BL to the common electrode block is provided in another pixelregion. The lower contact hole CTL and the upper contact hole CTU shouldbe covered with the masking layer BM. Thus, the pixels accommodating thelower contact hole CTL and the upper contact hole CTU have reducedmaximum aperture ratio then the pixels in between those two pixels.

To improve efficiency, the lower contact hole CTL and the upper contacthole CTU may be provided at certain selective pixels. For example, thelower contact hole CTL and the upper contact hole CTU may be provided inblue pixel regions. Luminance of blue pixels tends to be lower than theluminance of green or red pixels, even when they are provided in thesame size. With a poor luminance/size ratio, the actual amount ofluminance decreased by placing the contact holes is less in the bluepixel regions as compared to placing the contact holes in red and greenpixel regions. Therefore, in some embodiments, the lower contact holeCTL and the upper contact hole CTU at the opposite ends of the bypasslines BL may be arranged in the blue pixel regions.

As shown in the examples of FIG. 6A, the blue pixel regions foraccommodating a lower contact hole CTL and an upper contact hole CTU forconnection of a bypass line BL may be the pixels in the same row. Theintermediate pixel regions between the blue pixel region with the lowercontact hole CTL and the blue pixel region with the upper contact holeCTU in the same row includes pixel regions of other colors, such as ared pixel region, a green pixel region and/or a white pixel region.

A blue pixel region without a contact hole may also be included amongthe intermediate pixel regions between the two blue pixels accommodatingthe contact holes. That is, the interim section of a bypass line BLbetween the blue pixel region with the lower contact hole CTL and theblue pixel region with the upper contact hole CTL may be laid across oneor more blue pixel regions, which do not accommodate neither the lowercontact hole CTL nor the upper contact hole CTU therein.

It should be reminded that the bypass line BL and the gate lines GL areprovided in the same plane, and thus they are not arranged to overlapone another. As such, the aperture ratio of the intermediate pixelregions is also reduced by the bypass lines BL extending between thelower contact hole CTL and the upper contact hole CTU. In order tominimize the number of bypass pixel regions, that is, the pixel regionsof which the aperture ratio is reduced due to the bypass line BL, thelength of the bypass lines BL should be kept minimal. For this reason,the lower contact hole CTL and the upper contact hole CTU for each ofthe bypass lines BL may be provided in two closest blue pixel regions ofthe same row. In other words, the blue pixel region where the uppercontact hole CTU is formed in may be the first blue pixel region of thesame row, which comes after the blue pixel region with the lower contacthole CTL.

[Common Signal Line Detour]

In order to place the SL-BL contact region and the BL-VCOM region in theblue pixel regions, a common signal line SL under one data line DL mayneed to be partly detoured under another data line DL. For example, oneor more common signal lines SL at the right end of a common electrodeblock may run out of a blue pixel region to accommodate the BL-VCOMcontact region.

FIG. 15A is a schematic illustration of common signal lines SL providedwith a detour section DT, according to an embodiment of the presentdisclosure. Referring to FIG. 15A, a common signal line SL1 routed undera data line DL1 is provided with a detour section, which is skewedtoward the data line DL2. As such, the detour section DT of the commonsignal line SL1 runs under the data line DL2. In the example of FIG.15A, the detour section DT of the common signal line SL1 is a singlepixel long. That is, the detour section DT of the common signal line SL1extends in the Y-direction under the data line DL2 for a single pixel,then returns back under the data line DL1. However, the length of thedetour section DT is not limited as such. If desired, the detour sectionDT may continue for a plurality of pixels. In such cases, however, thedetour section DT of the adjacent common signal lines SL2, SL3, etc.would also be extended further.

The shift in the lane between the two data lines DL can be made at thepart of the common signal line SL crossing under the gate line GL. Inthis regard, the slanting portion of the common signal line SL may becovered under the gate line GL. Because the common signal line SLcarries modulation pulse signal during the touch scanning period, thusthe signal on the pixel electrode PXL can be affected by the signal onthe common signal line SL and cause unwanted visual artifacts on thescreen. Referring to FIG. 15B, the slanting portion of the common signalline SL may be routed in an angle such that the slanting portion doesnot go under the drain D of the TFT, which is not covered by the gateline GL. Further, some part of the common signal line SL may be routedin the X-direction along the gate line GL to be covered under the gateline GL. Further, the slanting portion of the common signal line SLshould be angled such that a sufficient margin can be provided betweentwo detouring sections of the common signal lines SL. In suitableembodiments, any two detouring sections of the common signal lines SLmay be spaced apart from each other by 5 um or more, and more preferablyby 6 um or more.

[Aperture Ratio Compensation]

Depending on the size and location, considerable difference in themaximum aperture ratio can result between the bypass pixels and thenormal pixels. The portion of the bypass line BL corresponding to thecontact holes for connecting the bypass line BL to the common signalline SL and to the common electrode block may be larger than otherportions of the bypass line BL. As such pixels where the contact holesin the lower planarization layer PLN-L for connecting the common signalline SL to the bypass line BL and in the upper planarization layer PLN-Ufor connecting the common electrode block to the bypass line BL may haveeven smaller maximum aperture ratio than other bypass pixels between thetwo. The differences in the aperture ratio of the pixels may be visuallynoticeable to a naked human eye, for instance as a moiré pattern or adim line, especially when the pixels of different aperture ratio arearranged in a simple repeated pattern.

Since it is the differences in the aperture ratio of pixels whichbecomes the visually noticeable pattern, lessening the differences inthe aperture ratio of the pixels would make the pattern less noticeable.Accordingly, in some embodiments, the masking layer BM may be configuredto compensate for the loss of aperture ratio in the bypass pixels.

Referring to FIG. 16, the masking layer BM includes a plurality ofstrips covering the data lines DL and the gate lines GL. In the presentdisclosure, the strips arranged in a longitudinal direction, coveringthe data lines DL, may be referred to as the data BM strip. The stripsarranged in horizontal direction, covering the gate lines GL and thebypass lines BL may be referred to as the gate BM strip. Further, aportion of each gate BM strip and each data BM strop corresponding to apixel is referred to as a gate BM section and a data BM section,respectively. In other words, a single gate BM strip includes aplurality of gate BM sections. Similarly, a single data BM stripincludes a plurality of data BM sections. These BM strips and the BMsections of the BM strips are arranged to intersect one another to setthe aperture ratio of the pixel regions, hence they are generallyreferred to as the black matrix pattern.

[Simple BM Pattern]

In some embodiments, aperture ratio of all pixels can be formed to beequal as depicted in FIG. 16. In this regard, the width of the gate BMstrips may be set to the width of the gate BM strip for the pixel regionwith the smallest maximum aperture ratio. For example, the gate BM stripfor all pixel regions may be provided in a width that is sufficient tocover upper the contact hole CTU and the lower contact hole CTL. In thisway, there will not be aperture ratio discrepancies between the bypasspixels and the normal pixels, albeit the overall aperture of all of thepixels will be reduced down to the smallest aperture of the pixels.

In some cases, reducing the aperture ratio discrepancies between thepixels accommodating the contact holes and the normal pixels may alonebe enough for eliminating the visually noticeable patterns to a certainlevel. As such, it is also possible that the width/alignment adjustedsection in a strip spans continuously for limited number of pixels. Forinstance, a continuous section of a gate BM strip, which spans from thepixel with the lower contact hole CTL until the pixel with the uppercontact hole CTU, may have a single width and aligned in the same way,even though the maximum aperture ratio that some of the pixels in thatparticular section may be greater than the maximum aperture ratio ofsome of other pixels of that section.

In some embodiments, the width of gate BM sections can be adjusted toreduce the discrepancy in aperture between the pixel regions. Forinstance, the widths of the gate BM sections corresponding to the normalpixels may be wider than the widths of the gate BM sectionscorresponding to the bypass pixels accommodating either the lowercontact hole or the upper contact hole. Also, the widths of the gate BMsections corresponding to the intermediate bypass pixels may be widerthan the widths of the gate BM sections corresponding to the bypasspixels accommodating either the lower contact hole or the upper contacthole. Further, the widths of the gate BM sections corresponding to thebypass pixels accommodating the upper contact hole may be wider than thewidth of the gate BM sections corresponding to the bypass pixelsaccommodating the lower contact hole. In this setting, the widths of thegate BM sections are adjusted to maximize the aperture of the bypasspixels accommodating the lower contact hole and the upper contact hole,then the widths of the gate BM sections corresponding to other pixelsare adjusted in reference to the aperture of those bypass pixels havingthe contact holes therein. This setting may provide higher overallaperture than the previous embodiments. However, the location of theaperture for each pixel can be skewed from one another, which may not bedesirable in some cases.

It should be noted that the differences in width among different thesections of the gate BM strips needs not be as large to make theaperture ratio of the pixels exactly the same. As shown in the exampleof FIG. 16, uniformity in aperture of bypass pixels and the normalpixels can tax the overall aperture of the pixels. Accordingly, in someembodiments, aperture of the bypass pixels may be from 80 percent to 95percent of the aperture of the normal. More preferably, aperture of thebypass pixels may be from 85 percent to 95 percent of the aperture ofthe normal. The aperture discrepancy at such a level may not be visuallynoticeable to a naked human eye, especially when coupled with severalother features described in the present disclosure.

[Asymmetric BM Pattern]

In such settings, however, the overall luminance of the display panelPNL suffers at some level. Accordingly, in some other embodiments,selective sections of the masking layer BM next to the pixel regions ofthe bypass pixels can be provided narrower than the other sections ofthe masking layer BM so that the aperture ratio discrepancies betweenthe bypass pixels and the normal pixels can be reduced. Also, selectivesections of the masking layer BM abutting the pixel regions of thebypass pixels can be shifted away or skewed from the sections abuttingthe normal pixels. In this way, the aperture ratio of the bypass pixelscan be increased while reducing or maintaining the aperture ratio of thenormal pixels. Accordingly, the difference in the aperture ratio of thebypass pixels and the normal pixels can be reduced, while maintainingthe overall luminance level of the display panel PNL.

For example, the width and/or the alignment of the sections in the dataBM strips and/or the gate BM strips can be adjusted to compensate theamount of aperture ratio difference between the bypass pixels and thenormal pixels. In the data BM strips and/or the gate BM strips, suchadjustments may be made on a pixel by pixel basis. That is, thewidth/alignment of the strips may be different between the pixel havingthe lower contact hole CTL, the pixel having the upper contact hole CTU,the intermediate pixels and the normal pixels.

In order to reduce the aperture ratio discrepancy among the pixels, someof the sections in a data BM strip can be asymmetrically arranged fromother sections of the same data BM strip. At the basic level, sectionsof the data BM strips bordering the bypass pixels can be narrower thanthe sections that are only bordering the normal pixels. In suchconfigurations, the sections of data BM strips placed between two normalpixels may be configured to be wider than other sections of the data BMstrip. That is, if any one of the pixels on the left and the right sidesof the section is a bypass pixel, then the width of the data BM strip atthat section may be narrower than the sections between two normalpixels. In this way, the reduction in the aperture ratio of the bypasspixels due to the bypass lines BL can be compensated to some degrees.

As shown in FIG. 17A, in some embodiments, sections in the data BM stripbetween two immediately adjacent normal pixels (e.g., section A) may beprovided with a width “W”, which is greater than the width of thesections of the data BM strip next to the first bypass pixel with thelower contact hole CTL, the second bypass pixel with the upper contacthole CTU and any of the intermediate bypass pixels between the firstbypass pixel and the second bypass pixel. That is, in each of the dataBM strips, data BM sections positioned next to a first bypass pixel(e.g., section C), a second bypass pixel or any intermediate bypasspixels between the first bypass pixel and the second bypass pixel (e.g.,section B) may be narrower than other data BM sections positionedbetween two immediately adjacent normal pixels (e.g., section A).

Further, in some embodiments, the data BM sections that are neighboringthe first bypass pixel, the second bypass pixel or any intermediatepixels between the first bypass pixel and the second bypass pixel mayhave substantially the same width, which is narrower than a width ofdata BM sections positioned between two immediately adjacent normalpixels. Accordingly, the differences in the width of the masking layerBM can compensate the aperture ratio discrepancy due to the placement ofthe bypass lines BL. However, it should be noted that the differences inwidth among different the sections of the data BM strips needs not be aslarge to make the aperture ratio of the pixels exactly the same. Asdescribed above, in some embodiments, aperture of the bypass pixels maybe from 80 percent to 95 percent of the aperture of the normal. Morepreferably, aperture of the bypass pixels may be from 85 percent to 95percent of the aperture of the normal. The aperture discrepancy at sucha level may not be visually noticeable to a naked human eye, especiallywhen configured with several other features described in the presentdisclosure.

By way of example, the width of the sections in the data BM stripneighboring the bypass pixels may be about 5 to 6 um while the width ofthe sections between the normal pixels may be about 7 to 8 um. The widthof the data line and the width of the common signal line SL should beequal to or less than the width of any given sections in the data BMstrip. In other words, the widths of the data line DL and the commonsignal line SL placed thereunder may set the narrowest width of the dataBM sections next to the bypass pixels.

As mentioned above, the pixel regions that are accommodating the contactholes may suffer the most in terms of aperture ratio by the bypass lineBL. Therefore, in some embodiments, the sections of data BM stripspositioned next to the pixel regions with the lower contact hole CTL andthe pixels regions with the upper contact hole CTU can be configured toprovide the maximum compensation of aperture ratio to those pixels. Assuch, in some of the embodiments, some of the data BM sections may beconfigured to be off-centered in relation to the center of the data lineDL placed thereunder as shown in sections “A”, “B” and “C” of FIG. 17B.

In FIG. 17B, the data BM sections between a pixel with a contact holeand a normal pixel may be configured asymmetrically from other sectionsof the data BM strip. FIGS. 17C-17E are cross-sectional views of thesections “A”, “B” and “C” in FIG. 17B, respectively. Referring to FIG.17C, the width of the data BM sections between the normal pixels (i.e.,wider portions of the data BM strips) may be greater than the width ofthe data line DL and the common signal line SL below. Thus, extra widthof the data BM section may be distributed equally on both sides on thedata line DL. By way of an example, if the data BM section between thetwo normal pixels has 3 um of extra width, then 1.5 um of the data BMsection can overhang on each side of the data line DL and/or the commonsignal line SL.

As described above, the data BM sections neighboring the pixel with acontact hole is asymmetrically configured with respect to other sectionsof the data BM strips. In this regard, the length in which the data BMsection overhangs beyond the edge of the data line DL toward the normalpixel may be greater than the length of the data BM section overhangingtoward the pixel with the contact hole. As shown in FIGS. 17D and 17E,the edge of the data BM section and the edge of the data line DL towardthe pixel with the contact hole can be arranged to be justly orotherwise vertically aligned to each other for the maximum apertureratio for the pixels with the contact hole. Further, in someembodiments, the length in which the data BM section overhangs towardthe pixel with a contact hole beyond the edge of the data line DLthereunder is shorter than the length in which the respective data BMsection overhangs toward the intermediate bypass pixel.

Note that the BM section should cover both the data line DL and thecommon signal line SL there under, and thus, the edge of the data BMsection and the edge of the common signal line SL may be aligned to eachother toward the pixel with the contact hole. In other words, the edgeof the data BM section can be aligned with either the edge of the dataline DL or the edge of the common signal line SL, whichever is closer tothe pixel with the contact hole.

The light from a light source may be passed through a color filterlayer, which would set the color of light emitted from each of the pixelregion. In some embodiments, the color filter layer and the maskinglayer BM may be provided on a second substrate, which is different fromthe first substrate where the array of TFT is located. Here, the colorfilter layer may be arranged such that the masking layer BM is providedfurther away from the first substrate than the color filter layer.Alternatively, the color filter layer and the masking layer BM may beprovided on a second substrate, and arranged such that the masking layerBM is provided closer toward the first substrate where the array of TFTsis provided than the color filter layer. The light from the display canbe projected from the first substrate and extracted toward the secondsubstrate, and the masking layer BM positioned closer toward the firstsubstrate then the color filter layer can help in suppressing lightintended for one pixel leaking into an adjacent pixel.

In some embodiments, the masking layer BM may be provided closer to thelight source than the color filter layer. Providing the masking layer BMcloser to the light source allows to control the angle of the light fromthe light source to the color filter layer with more acuity, which inturn, makes it possible to suppress light leakage and/or color washoutissues at a reduced width of the masking layer. Accordingly, thediscrepancy in the aperture ratio between the normal pixel and thebypass pixels can be dealt with the asymmetric BM strips with a lowerrisk of such light leakage or the color washout issues.

[Wavy Bypass Line]

In some embodiments, the location and the shape of the bypass line BLcan be adjusted to maximize the aperture ratio of the bypass pixels.Depending on the shape of the gate line GL, some parts of the bypassline BL can be arched toward the gate line GL, while keeping the minimummargin from the gate line GL. By eliminating the space wasted betweenthe gate line GL and the bypass line BL, the area that needs to becovered by the masking layer BM can be reduced for the bypass pixels.

FIGS. 18A and 18B illustrate an exemplary configuration of the bypassline BL, which may be provided in the display panel PNL for greateraperture ratio of the bypass pixels. With both the gate line GL and thebypass line BL being patterned from the second metal layer M2, they mustbe spaced apart from each other by a minimum margin (denoted as G2G). Asa non-limiting example, the minimum margin G2G between the gate line GLand the bypass line BL may be about 5 um. As shown, the gate line GLincludes a plurality of gate electrodes that project out toward theactive channel of the TFTs from the main routing portion of the gateline GL. There is an indented open area between every two adjacent gateelectrodes for connecting the drain of the TFT and the pixel electrodePXL. As such, the part of the bypass line BL next to the indented openarea can be arched in toward the indented open area until the minimummargin is reached.

Accordingly, the bypass line BL has a sign-wave form shape, which partsof the bypass line BL is curved in and out. More specifically, parts ofthe bypass line BL arches in toward an indented open area between twogate electrodes, and parts of the bypass line BL arches out in theopposite direction at the gate electrode portion of the gate line GL. Inthe example shown in FIGS. 18A and 18B, both the SL-BL contact regionand the BL-VCOM contact region are provided in blue pixel regions. Thebypass line BL laid between these two blue pixel regions include threearched-in portions and three arched-out portions. Also, the gate line GLpositioned nearest to the bypass line BL has the plurality of indentedopen area with the opening toward the nearest bypass line BL. Eacharched-in portion is provided between the two immediately adjacent datalines DL. Each arched-out portion is provided between two immediatelyadjacent pixel regions. Accordingly, each arched-out portion of thebypass line BL is provided between two arched-in portions of the bypassline. Even though the bypass line BL is provided with such a sign-waveshape, all parts of the bypass line BL is distanced away from thenearest gate line GL by at least the minimum margin G2G.

[Common Signal Line with Light Shield]

Considering the minimum margin G2G between the gate line GL and thebypass line BL discussed above, greater aperture ratio can be achievedby reducing the size of the gate electrode. In embodiments which theTFTs of the display panel PNL are the bottom gated inverted staggeredtype TFTs, the gate electrode serves as a light shield LS for the activechannel of the TFT. To serve as the light shield LS, the gate electrodemay need to be provided in a larger dimension than it needs to be forsimply controlling on/off state of the TFT. The extra length of the gateelectrode outside the edge of the active of the TFT for light shieldingpurposes may be referred to as the gate shield GS. However, thedimension of the gate electrode, in particular the size of the gateshield GS, can be reduced if the active of the TFT can be shielded fromthe light by another structure.

Accordingly, in some embodiments, some of the common signal lines SL maybe provided with a light shield LS. More specifically, the light shieldLS may be projected out from the routing portion of the common signalline SL. The light shield LS is positioned at the end of the gateelectrode facing the bypass line BL. In the pixels provided with thelight shield LS, the width of the gate shield GS can be reduced. Inother words, the light shield LS, which patterned from the first metallayer M1, is provided to compensate for the reduced width of the gateshield GS. When the width of the gate shield GS is reduced, the bypassline BL can be placed more toward the gate line GL, and this would allowa thinner gate BM at the bypass pixels.

As shown in FIG. 18A, the light shield LS may not be needed in thenormal pixel as the normal pixel has the greatest aperture ratio evenwithout the light shield LS. In such cases, the gate electrode isprovided with the gate shield GS of a sufficient width. For instance,the width of the gate shield GS in the Y-direction may be 4 um orgreater.

The common signal line SL between the normal pixel and the first bluepixel is provided with the light shield LS. The common signal line SLincludes a connection portion that projects out from the routingportion. In such cases, the connection portion can be enlarged and serveas the light shield LS at the same time as shown in FIG. 18A.

Each of the common signal lines SL positioned between the first bypasspixel and the last bypass pixel is also provided with the light shieldLS. Since these common signal lines SL do not have the connectionportion, the light shield LS of these common signal lines SL are not aslarge as the one in the first bypass pixel.

FIG. 18B is an enlarged view showing an exemplary configuration of thecommon signal lines SL with the light shield LS. As shown, the lightshield LS can be positioned next to the gate shield GS of the bypassline BL side. It should be noted that the gate electrodes of the bypasspixels still include the gate shields GS, although at a much narrowerwidth than the gate shield GS of the normal pixel. As mentioned above,the reduced width of the gate shield GS in the bypass pixels shifts theboundary of the minimum margin G2G between gate line GL and the bypassline BL, and thus the bypass line BL can also shift toward the gate lineGL without impinging upon the minimum margin G2G from the gate line GL.

As shown, the width of the light shield LS can be greater than the widthof the gate shield GS provided in the normal pixel. As such, the lightshield LS compensates for the reduced width of the gate shield GS in thebypass pixels. In this regard, the light shield LS in the bypass pixelmay be configured to provide even a greater coverage than the gateshield GS of the normal pixel. In other words, the distance between theedge of the active and the edge of the light shield LS on the bypassline BL side may be greater than the distance between the edge of thegate shield GS and the edge of the active. Further, the light shield LSin the bypass pixels may be arranged to at least partially overlap withthe gate shield GS to ensure that the external light does not reach theactive of the TFT. In some cases, part of the light shield LS can bepositioned to partially overlap with the active of the TFT.

In the example shown in FIG. 18B, the light shield LS is configured toreduce the width of the gate electrode, and shift the bypass line BL forgreater aperture ratio of the bypass pixels. The light shield LS isarranged to reduce the gate shield in vertical direction (i.e.,Y-direction). However, in some embodiments, the light shield LS may alsobe configured to reduce the gate shield GS in the horizontal direction(i.e., X-direction). As depicted in FIG. 18C, the light shield LS can beextended under the gate shield GS toward the drain-pixel contact hole atthe indented open area. In this setting, the light shield LS may notcontribute much for the aperture ratio of the pixels. However, thereduced gate shield GS toward the drain-pixel contact hole can help infurther reducing the Cgs of the TFT and the AVp (kick back voltage).

[Contact Bridge]

As described above, in some embodiments, a contact bridge patterned fromthe third metal layer M3 may be placed at the BL-VCOM contact region. Insuch embodiments, the minimum margin between the contact bridge andother metal structures patterned from the third metal layer M3 needs tobe considered. For example, the minimum margin must be maintainedbetween the contact bridge and the drain electrode of the TFT (denotedas D2D). Also, the minimum margin D2D must be maintained between thecontact bridge and the data line DL. The minimum margin D2D which mustbe maintained between the metal structures patterned from the thirdmetal layer M3 may be greater than the minimum margin G2G to bemaintained between the gate line GL and the bypass line BL. As such, itis difficult to reduce the width of the gate BM at the BL-VCOM contactregion even when the common signal line SL is provided with the lightshield LS to reduce the width of the gate shield GS. Also, due to theminimum margin D2D from the data lines DL, the location of the uppercontact hole CTU in the bypass pixel may be limited.

Accordingly, in some embodiments, the contact between the bypass line BLand the common electrode block at the BL-VCOM contact region is madewithout the contact bridge. FIG. 19A illustrates configurations ofBL-VCOM contact area with and without the contact bridge. Connecting thebypass line BL and the common electrode block via the upper contact holeCTU without the use of the contact bridge may be achieved by adjustingthe order in which the contact holes are formed during the manufacturingof the display panel PNL.

FIG. 19B is an exemplary manufacturing steps of the display panel PNLwithout the contact bridge, according to an embodiment of the presentdisclosure. For brevity, the method is explained from the step ofpatterning the second metal layer M2 on the lower planarization layerPLN-L. In step 1, the second metal layer M2 is patterned to form thegate lines GL and the bypass line BL. In step 2, the gate insulationlayer GI and the semiconductor layer SEM are provided on the gate linesGL. Unlike the previous example described in reference to FIGS. 7A and7B, in this case, contact hole formation through the semiconductor layerSEM and the gate insulation GI for exposing the bypass line BL ispostponed. The third metal layer M3 can be patterned to provide the datalines DL and source/drain of the TFT. In this embodiment, however, thecontact bridge shown in FIGS. 7A and 7B is not patterned in the BL-VCOMcontact region. Patterning of the semiconductor layer SEM can be donealong with the patterning of the third metal layer M3, or may be doneseparately prior to the patterning of the third metal layer M3.

In this case, the contact bridge at the BL-VCOM contact region is nolonger needed as the bypass line GL at the BL-VCOM contact region iscovered under the gate insulation layer GI. In step 3, the passivationlayer PAS3 is provided. As shown in FIG. 19B, the passivation layer PAS3is on the gate insulation layer GI at the BL-VCOM contact region. Instep 4, the upper planarization layer PLN-U is provided so that the datalines DL and the source/drain of the TFTs are covered under the upperplanarization layer PLN-U. Then, a contact hole is formed through theupper planarization layer PLN-U. The upper contact hole CTU is formed atto expose the BL-VCOM contact region. At this stage, the passivationlayer PAS3 and the gate insulation layer GI still remains over thebypass line BL at the BL-VCOM contact region. Similarly, a contact holecan be formed through the upper planarization layer PLN-U to exposedrain region of the TFT. The drain region, which is exposed through thecontact hole of the upper planarization layer PLN-U, may also be coveredby the passivation layer PAS3 and the gate insulation layer GI.

After the formation of the contact hole through the upper planarizationlayer PLN-U, in step 5, the passivation layer PAS3 and the gateinsulation layer GI at the drain region of the TFT and the BL-VCOMcontact region can be etched at the same time to expose the bypass lineBL. Once the bypass line is exposed, in step 6, the transparentelectrode layer (e.g., ITO) can be deposited to be in contact with thebypass line BL through the upper contact hole CTU. In this way, a directcontact between the bypass line BL and the common electrode block can bemade without using the contact bridge formed from the third metal layerM3.

Without the contact bridge at the BL-VCOM contact region, the bypassline BL can be positioned closer to the gate line GL so long as theminimum margin between the bypass line BL and the gate line GL ismaintained. As described above, the width of the gate shield GS can bereduced by providing the light shield LS, which is patterned from thefirst metal layer M1, and reduce the width of the gate BM. Further,contact portion of the bypass line BL at the BL-VCOM contact region canbe shifted toward left side or right side toward the data lines DL,which would allow for more efficient placement of the bypass line BLwithin the pixel region.

[Bypass Line Shifting]

Although the aperture ratio discrepancy among the pixels is the rootcause of the visual artifacts, it is the repeated arrangement of suchpixels, which makes the visual artifacts stand out and noticeable to anaked human eye. It would be difficult to perceive the relatively lowluminance of a single isolated set of bypass pixels. However, multiplesets of bypass pixels arranged in a repeated pattern forms a pattern oflow luminance region and a high luminance region in the matrix, which ismuch more perceptible to a naked eye. Some pattern is inevitable in thearrangement of the bypass lines in the matrix, but the pattern can beless noticeable when it becomes complex enough.

Here, the basic idea is to provide variations in the arrangement ofbypass lines BL in the matrix of pixel regions rather than placing themin a simple linear order in vertical or horizontal directions.Accordingly, in some embodiments, a set of bypass lines BL connected toa common electrode block includes a bypass line BL from the set ofbypass lines BL is displaced from at least one other bypass line BL ofthe same set. More specifically, the pixel region accommodating thelower contact hole CTL for a bypass line BL of the set of bypass linesBL is placed in a different row and a different column from the pixelregion accommodating the lower contact hole CTL for at least one otherbypass line BL of the same set.

As described in above, each common electrode block may be connected to aplurality of common signal lines SL as well as dummy lines DML. Further,a single common signal line or a single dummy line DML may be connectedto the common electrode block by using multiple bypass lines BL. Assuch, the set of bypass lines BL connected to the common electrode blockmay be the bypass lines BL connected to a single common signal line SL,a plurality of common signal lines SL, a single dummy line DML, aplurality of dummy lines DML or a combination of the above.

FIG. 20A shows an exemplary configuration of a set of bypass lines for acommon electrode block. In this example, the line #1 is connected to thecommon electrode block via two bypass lines (BL 1-1 and BL 1-2). Thelower contact holes CTL for each of the bypass lines BL 1-1 and BL 1-2are provided in the same column of pixel regions. Similarly, the line #2is connected to the common electrode block via two bypass lines (BL 2-1and BL 2-2), and the lower contact holes CTL for the each of the bypassline BL 2-1 and BL 2-2 are provided in the same column of pixel regionsas each other. The line #1 and the line #2 may each be either a commonsignal line SL or a dummy line DML.

As shown, the pixel regions with the lower contact holes CTL for thebypass lines BL connected to the line #1 and the pixel regions with thelower contact holes CTL for the bypass lines BL connected to the line #2are provided in different rows. Skewing the placement of contact holesfor the bypass lines BL, at least to different rows from one another,can help in suppressing the visually noticeable pattern, such as themoiré effect.

As mentioned above, the lower contact holes CTL and the upper contactholes CTU may be provided in the blue pixel regions. Each of the uppercontact holes CTU for the bypass lines BL may also be placed in a bluepixel region, which can be in the same row as the blue pixel thataccommodates the lower contact hole CTL for the respective bypass lineBL. It should be noted that the column of pixel regions including thepixels accommodating the contact holes needs not be formed entirely ofblue pixels regions. Instead, the column may be formed of pixel regionswith many different colors including the blue pixel regions where thecontact holes are accommodated in.

FIG. 20B illustrates another exemplary configuration of a set of bypasslines BL connected to the common electrode block. Similar to theprevious example, the line #1 and the line #2 are connected to the samecommon electrode via one or more of bypass lines BL. In this particularexample, however, some bypass lines BL extend to the left side whilesome other bypass lines BL extend to the right side of the underlyinglines that they are connected to.

By way of an example, the bypass line BL 1-1 connected to the line #1extends from the lower contact hole CTL to the upper contact hole CTU,which is provided further on the right side of the lower contact holeCTL for the bypass line BL 1-1. The bypass line BL 2-1 connected to theline #2 is extends from the lower contact hole CTL to the upper contacthole CTU, which is provided on the left side of the lower contact holeCTL for the bypass line BL 2-1. Although not depicted in FIG. 7B, otherbypass lines connected to the line #1 and the line #2 may also beconfigured in the similar way as the bypass line BL 1-1 and the bypassline BL 2-1.

Also, even among the bypass lines connected to the same common signalline SL, some bypass lines can be arranged to extend toward one side ofthe common signal line SL while some of the other bypass lines arearranged to extend toward in the other side. For instance, the bypassline BL 1-1 may extend toward the right side of the line #1, while thebypass line BL 1-2 extends toward the left side of the line #1 asdepicted in FIG. 20C. That is, the lower contact hole CTL for the bypassline BL 1-1 and the lower contact hole CTL for the bypass line BL 1-2are provided in the pixel region of the same column. On the other hand,the upper contact holes CTU for the bypass line BL 1-1 and the bypassline BL 1-2 are provided at the opposite sides of the line #1 from eachother. Since the bypass lines are formed in the second metal layer M2(e.g., gate metal layer), they can be transversely extended across theline #1 (i.e., the first metal layer M1) and the data line DL (i.e., thethird metal layer M3) placed thereon.

Although the lower contact holes CTL for the bypass lines BL weredepicted as being provided in the pixel regions of the same column, insome other embodiments, the lower contact hole CTL for each of thebypass lines BL can be placed in pixel regions of different columns evenwhen they are connected to the same common signal line SL (or the samedummy line DML).

FIG. 20D illustrates yet another exemplary configuration of the bypasslines BL connected to the same common electrode block. Similar to theprevious example, the line #1 is connected to a common electrode blockvia a plurality of bypass lines BL. Unlike the previous examples,however, the lower contact holes CTL for some of the bypass lines BL areprovided in a pixel region away from the common signal line SL (or thedummy line DML).

Referring to FIG. 20D, the lower contact hole CTL for connecting thebypass line BL 1-1 to the line #1 is provided in the pixel region in acolumn A. The lower contact hole CTL for connecting the bypass line BL1-2 to the line #1 is provided in the pixel region in a column B. Also,the lower contact hole CTL for connecting the bypass line BL 1-3 to theline #1 is provided in the pixel region in a column C. To this end, theline #1 is provided with the a plurality of contact portions projectedout from the routing portion of the line #1, which are extended to thepixel regions of different columns where the contact is made with thecorresponding bypass lines. To put it in another way, some contactportions of the line #1 may have a different length than others. Asdescribed before, the dummy line DML can be divided into multiple piecesto provide a passage for the contact portions to pass across and reachthe pixel regions where the lower contact hole CTL are placed in. Inthis configuration, some contact portions would pass across a more orless number of dummy lines DML than other contact portions.

In FIG. 20D, the lower contact holes CTL for all of the bypass lines BLconnected the line #1 were provided in the pixel regions of differentcolumns. However, it should be appreciated that not all of the lowercontact holes SL for the bypass lines BL needs to be provided in thepixel regions of different columns. In other words, some of the lowercontact hole CTL for the bypass lines BL may still be provided in thesame column with the lower contact holes CTL for other bypass lines BL.

Moreover, the contact portions of the line #1 can be arranged not justin X-direction but also in Y-direction as well. In such cases, the partof the contact portion being arranged in Y-direction can be extendedunder a data line DL, which is different from the one that is placed onthe routing portion of the common signal line SL.

Referring to the example shown in FIG. 20D, the routing portion of theline #1 extends underneath the data line DL. The contact portions areprojected out from the routing portion in the X-direction. A part of thecontact portion being in contact with the bypass line BL 1-3 extends inthe Y-direction underneath the data line DL_2, which then reaches thepixel region where the lower contact hole CTL is located. The contactportion being in contact with the bypass line BL 1-3 would be extendedacross a gate line GL. Of course, the number of gate lines GL which thecontact portion crosses over varies by the length in which the part ofcontact portion extends in the Y-direction. Accordingly, some lowercontact holes CTL can be provided in the pixel regions of the samecolumn even though the contact portions are provided in differentlengths.

In FIG. 20D, the contact portions of the line #1 were projected out tothe right side of the routing portion. However, it should be appreciatedthat some common signal lines SL or dummy lines DML may include contactportions that are projected out in the opposite direction anothercontact portion of the same line.

In FIGS. 20A-20D, the configuration of bypass lines BL have beendescribed in reference to just single common electrode block. However,it should be noted that the common electrode blocks in a display panelPNL need not be configured in the same way as each other. In otherwords, configuration of the common signal lines SL and the bypass linesBL in one common electrode block may differ from the configuration ofthose in another common electrode block. In this way, more complexbypass line BL pattern can be provided in the display panel PNL as awhole so that it becomes difficult for a user to visually recognize theaperture ratio differences caused by the bypass lines BL.

FIGS. 21A and 21B illustrate an exemplary configuration of the displaypanel PNL at the region between two adjacent common electrode blocks.Since the common electrode VCOM is divided in several common electrodeblocks, a space (denoted as COMM. Space in FIGS. 21A and 21B) existsbetween two adjacent common electrode blocks. In this space, theelectrical field for controlling the liquid crystal molecules may bedisrupted due to the lack of common electrode block, and may resultvarious visual defects. As such, a piece of transparent electrode, whichis patterned along with the pixel electrode PXL, is provided in the“COMM. Space”. Such a transparent electrode is referred to as the“shield ITO” in the present disclosure.

[Shield ITO]

Referring to FIGS. 21A and 21B, a shield ITO is provided between thecommon electrode blocks #1 and #2. In order to keep the common electrodeblocks #1 and #2 separated from each other, the shield ITO is formedfrom the transparent electrode layer of the pixel electrode PXL.Accordingly, a passivation layer PAS4 is interposed between the shieldITO and the common electrode blocks #1 and #2. However, the shield ITOneeds to be connected to either the common electrode block #1 or #2 inorder to generate electric field for controlling the liquid crystalmolecules at the COMM. Space. In the embodiment depicted in FIGS. 21Aand 21B, the shield ITO is in contact with the common electrode block #1via a contact hole through the passivation layer PAS4 at the ITO shieldcontact region. Of course, the configuration of the shield ITO can bereversed and the shield ITO can be connected to the common electrodeblock #2.

The ITO shield contact region may affect the maximum aperture ratio ofthe pixel region. Accordingly, the shield ITO at the shield ITO contactregion can be positioned to at least partially overlap with the gateline GL of the adjacent row of pixels as depicted in FIG. 21A. In someembodiments, the pixel electrode PXL can be provided in a comb shape tocompensate further for the aperture ratio AR affected by the ITO shieldcontact region. In this case, at least some teeth of the comb shapedpixel electrode PXL can be extend further toward the gate line GL for ofthe adjacent row of pixel as depicted in FIG. 21A. In the exampledepicted in FIG. 21A, one of the teeth EXT that is not intercepted bythe ITO shield at the ITO shield contact region is extended toward thegate line GL. Similar to the ITO shield at the ITO shield contactregion, the tooth of the pixel electrode PXL extended next to the ITOshield contact region may be at least partially overlap with the gateline GL. In such a setting, the extended tooth of the pixel electrodePXL can generate electric field in conjunction with the common electrodeblock #1 provided thereunder, which would contribute in minimizing thewidth of the gate BM.

The embodiments have been described with the common signal lines SLextended along under the corresponding data lines DL. However, featuresdescribed herein can also be used even when the common signal lines SLare arranged to extend along under the gate lines GL. Further,embodiments have been described in the context of LCD display panel thehaving the pixel-top configuration. However, features described in thepresent disclosure can be equally applied in a display panel having theVCOM-top configuration, in which the layer of common electrode blocksand the layer of pixel electrodes are positioned in the reverse orderfrom the examples depicted in the figures of the present disclosure. Inthe embodiments having the VCOM-top configuration, the contact hole atthe BL-VCOM contact region or at the SL-VCOM contact region is formedthrough the passivation layer PAS4 to connect the common electrode blockto the bypass line or directly to the common signal lines SL,respectively.

In this disclosure, many of the features have been described inreference to the embodiment which the common signal line SL and thecommon electrode block is connected via a bypass line BL. However,unless a specific feature is described as exclusive to the embodimentswith the bypass lines, features may be applicable in the embodimentwhich the common signal line SL and the common electrode block is indirect contact with each other via a contact hole through the upperplanarization layer PLN-U and the lower planarization layer PLN-L.

In the present disclosure, all of the embodiments have been described ashaving the common signal lines SL and the data lines positioned tooverlap one another. The width of the common signal lines SL can beequal to the width of the data lines DL. However, it should be notedthat the width of the common signal lines SL and the width of the datalines DL can differ from each other. With the common electrode beingprovided in a plurality of common electrode blocks, the field at theregion between the two adjacent common electrode blocks can be differentfrom other regions on the common electrode block. As such, controllingof the liquid crystal molecules over such regions may be difficult, andthe light from the backlight can leak into the pixels near such regions.

Accordingly, a data line DL and a common signal line SL can be placed inthe region between the two adjacent common electrode blocks. This way,the data line DL and the common signal line SL can be used to block thelight from the backlight. The width of the data lines DL and the widthof the common signal lines SL can be adjusted according to the distancebetween the two adjacent blocks. In this regard, increasing the width ofthe common signal lines SL can help reduce the resistance and lower theRC delay on the common signal lines SL. In the embodiments with thecommon signal lines SL disposed under the data lines DL, the width ofthe common signal lines SL can be greater than the width of the datalines DL. Since the common signal lines SL are placed further away fromthe common electrode blocks and the pixel electrodes than the data linesDL, managing the coupling capacitance may be easier for the commonsignal lines SL than the data lines DL.

In the embodiments disclosed in the present disclosure, the commonsignal lines SL are arranged under the data lines DL (or under the gatelines GL) and routed from the transparent electrode block to the driver(e.g., touch driver TD) in the non-display area directly across thedisplay area. By routing the common signal lines SL directly across thedisplay area, the size of the in display area at the side of the panelcan be reduced. Further, the thickness of the passivation layer betweenthe pixel electrode PXL and the common electrode blocks can be keptminimal to increase the capacitance of the pixel. Since, the commonsignal lines SL can be spaced farther away from the common electrodeblocks, they can be provided with a desired thickness to decrease RCdelays during touch-sensing period. In addition, there is no fringefield generated between the common electrode blocks and the commonsignal lines SL as the common electrode blocks positioned above thecommon signal lines SL. This effectively solves the light leakageproblem caused by having the common signal lines SL in the same layer asthe pixel electrode PXL.

In the embodiments of the present disclosure, the transparent electrodeand the common signal lines SL are described in reference to a touchrecognition enabled LCD device. However, the use of the transparentelectrode (e.g., common electrode block) and the common signal line SLis not limited to displaying images from the panel and identifying thelocation of touch inputs. The functionalities of the transparentelectrode and the common signal lines SL during other periods are notlimited to activating the pixels (e.g., LCD pixel) as described above.In addition to touch-sensing functionality, the common electrode blocksand the common signal lines SL may be used in measuring amount of touchpressure on the screen, generating vibration on the screen or actuatingelectro-active materials in the panel.

For example, some embodiments of the display panel PNL may include alayer of deformable material. The common electrode blocks may beinterfaced or positioned near the deformable material, and loaded withvoltage signals to measure electrical changes caused by the deformationof the deformable material. In such cases, the common electrode blockscan measure the amount of pressure on the display panel PNL in additionto the location of the touch inputs. In some embodiments, the deformablematerial may be electro-active materials, which the amplitude and/or thefrequency of the material can be controlled by electrical signals and/orelectrical field. The examples of such deformable materials includepiezo ceramic, electro-active-polymer and the like. In such embodiments,the common electrode blocks can be used to bend the deformable materialinto desired directions and/or to vibrate at desired frequencies,thereby providing tactile and/or texture feedback on the display panelPNL.

Although various embodiments are described with respect to displaypixels, one skilled in the art would understand that the term displaypixels can be used interchangeably with the term display sub-pixels inembodiments in which display pixels are divided into sub-pixels. Forexample, some embodiments directed to RGB displays can include displaypixels divided into red, green, and blue sub-pixels. In other words, insome embodiments, each sub-pixel can be a red (R), green (G), or blue(B) sub-pixel, with the combination of all three R, G and B sub-pixelsforming one color display pixel.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope of the inventions. Thus, it is intendedthat the present disclosure covers the modifications and variations ofthis invention provided they come within the scope of the appendedclaims and their equivalents.

What is claimed is:
 1. A display panel, comprising: a plurality ofcommon signal lines on a substrate, the plurality of common signal linesconfigured to transmit signals to and from a touch driver; a lowerplanarization layer on the plurality of common signal lines; a bufferlayer provided on the lower planarization layer, the buffer layerincluding at least one of a silicon nitride layer and a silicon oxidelayer; a plurality of thin-film transistors on the buffer layer, saidplurality of thin-film transistors having a coplanar structure; an upperplanarization layer on the plurality of thin-film transistors; and aplurality of transparent electrode blocks on the upper planarizationlayer, each of the transparent electrode blocks connected to at leastone of the common signal lines via at least one of a plurality of bypasslines interposed between the lower planarization layer and the upperplanarization layer, wherein each of the common signal lines has aplurality of light shield portions, each of the light shield portionsarranged under an active channel region of one of the plurality ofthin-film transistors.
 2. The display device of claim 1, wherein each ofthe plurality of light shield portions projects out from a routingportion of the respective common signal line which extends along one ofa plurality of data lines, and each of the light shield portions atleast partially overlaps with one of a plurality of gate lines.
 3. Thedisplay device of claim 1, wherein said plurality of thin-filmtransistors comprise an oxide metal semiconductor layer.
 4. The displaydevice of claim 3, wherein each of the plurality of thin-filmtransistors includes a gate electrode projected out from one of theplurality of gate lines, and wherein at least a part of each lightshield portion overhangs outside an outer edge of the gate electrode ofthe respective thin-film transistor.
 5. The display device of claim 1,wherein at least some of the light shield portions are in contact withone of the plurality of bypass lines via a lower contact hole throughthe lower planarization layer.
 6. The display device of claim 1, whereinthe lower planarization layer includes an organosiloxane hybrid layerincluding Si—O monomer and polymer.
 7. The display device of claim 1,further comprising one or more passivation layers provided under thelower planarization layer.
 8. The display device of claim 7, whereinsaid at least one of the passivation layers is provided on the pluralityof common signal lines.
 9. The display device of claim 7, wherein thecommon signal lines are formed of a stack of multiple metal layersincluding a copper layer.
 10. The display device of claim 1, wherein thetouch driver is configured to measure capacitance changes on theplurality of separated transparent electrode blocks.
 11. The displaydevice of claim 10, wherein the plurality of transparent electrodeblocks are configured to function as a self-capacitance touch sensor.12. The display device of claim 10, wherein the plurality of transparentelectrode blocks are configured to function as a mutual-capacitancetouch sensor.
 13. The display device of claim 10, further comprising alayer of organic-light emitting diode (OLED) elements, each of the OLEDelements connected to at least one of the plurality of thin-filmtransistors.
 14. The display device of claim 10, further comprising acolor filter substrate and a layer of liquid crystal moleculesinterposed between the substrate and the color filter substrate, whereineach pixel of the display device is provided with a pixel electrodearranged to generate electric field in conjunction with one of thetransparent electrode blocks to control the liquid crystal molecules atthe respective pixel.
 15. An electronic device having a touch sensorintegrated display panel, comprising: a plurality of common signal lineson a substrate, each of the common signal lines having a routing portionand a light shield portion; a lower planarization layer on the pluralityof common signal lines; a plurality of thin-film transistors placedabove the lower planarization layer, each of the thin-film transistorshaving a gate electrode, a source electrode and a drain electrode all ofwhich are provided on a semiconductor layer; and an upper planarizationlayer on the plurality of thin-film transistors; a layer of separatedtransparent electrode blocks arranged on the upper planarization layer,each transparent electrode block electrically connected to a touchdriver via a signal path, which includes at least one of the commonsignal lines placed under the lower planarization layer, wherein thelight shield portion of each of the plurality of common signal lines ispositioned to overlap with the semiconductor layer of one of theplurality of thin-film transistors.
 16. The electronic device having thetouch sensor integrated display panel of claim 15, wherein thesemiconductor layer of the plurality of thin-film transistors is anoxide metal semiconductor layer.
 17. The electronic device having thetouch sensor integrated display panel of claim 15, further comprising aplurality of bypass lines interposed between the lower planarizationlayer and the upper planarization layer, wherein each transparentelectrode block is connected to the corresponding signal path via atleast one of the plurality of bypass lines.
 18. The electronic devicehaving the touch sensor integrated display panel of claim 15, furthercomprising: a gate driver configured to provide a scan signal on firstset of gate lines during a first display period and to provide the scansignal on a second set of gate lines, which follows the first set ofgate lines, during a second display period, the first display period andthe second display period being parts of a same frame and separated byan intermediate touch scan period during which no gate lines areprovided with the scan signal, wherein the touch driver is configured tocommunicate with each of the separated transparent electrode blocksduring the intermediate touch scan period to identify touch inputsreceived at the display panel.
 19. The electronic device having thetouch sensor integrated display panel of claim 15, further comprising alayer of organic-light emitting diode (OLED) elements, wherein each ofthe OLED elements is connected to at least one of the plurality ofthin-film transistors.
 20. The electronic device having the touch sensorintegrated display panel of claim 15, further comprising a color filterlayer and a layer of liquid crystal molecules interposed between thesubstrate and the color filter substrate.